1 /* $OpenBSD: clientloop.c,v 1.213 2009/07/05 19:28:33 stevesk Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The main loop for the interactive session (client side). 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * 38 * SSH2 support added by Markus Friedl. 39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 #include "includes.h" 63 64 #include <sys/types.h> 65 #include <sys/ioctl.h> 66 #include <sys/param.h> 67 #ifdef HAVE_SYS_STAT_H 68 # include <sys/stat.h> 69 #endif 70 #ifdef HAVE_SYS_TIME_H 71 # include <sys/time.h> 72 #endif 73 #include <sys/socket.h> 74 75 #include <ctype.h> 76 #include <errno.h> 77 #ifdef HAVE_PATHS_H 78 #include <paths.h> 79 #endif 80 #include <signal.h> 81 #include <stdarg.h> 82 #include <stdio.h> 83 #include <stdlib.h> 84 #include <string.h> 85 #include <termios.h> 86 #include <pwd.h> 87 #include <unistd.h> 88 89 #include "openbsd-compat/sys-queue.h" 90 #include "xmalloc.h" 91 #include "ssh.h" 92 #include "ssh1.h" 93 #include "ssh2.h" 94 #include "packet.h" 95 #include "buffer.h" 96 #include "compat.h" 97 #include "channels.h" 98 #include "dispatch.h" 99 #include "key.h" 100 #include "cipher.h" 101 #include "kex.h" 102 #include "log.h" 103 #include "readconf.h" 104 #include "clientloop.h" 105 #include "sshconnect.h" 106 #include "authfd.h" 107 #include "atomicio.h" 108 #include "sshpty.h" 109 #include "misc.h" 110 #include "match.h" 111 #include "msg.h" 112 #include "roaming.h" 113 114 /* import options */ 115 extern Options options; 116 117 /* Flag indicating that stdin should be redirected from /dev/null. */ 118 extern int stdin_null_flag; 119 120 /* Flag indicating that no shell has been requested */ 121 extern int no_shell_flag; 122 123 /* Control socket */ 124 extern int muxserver_sock; 125 126 /* 127 * Name of the host we are connecting to. This is the name given on the 128 * command line, or the HostName specified for the user-supplied name in a 129 * configuration file. 130 */ 131 extern char *host; 132 133 /* 134 * Flag to indicate that we have received a window change signal which has 135 * not yet been processed. This will cause a message indicating the new 136 * window size to be sent to the server a little later. This is volatile 137 * because this is updated in a signal handler. 138 */ 139 static volatile sig_atomic_t received_window_change_signal = 0; 140 static volatile sig_atomic_t received_signal = 0; 141 142 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 143 static int in_non_blocking_mode = 0; 144 145 /* Common data for the client loop code. */ 146 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 147 static int escape_char1; /* Escape character. (proto1 only) */ 148 static int escape_pending1; /* Last character was an escape (proto1 only) */ 149 static int last_was_cr; /* Last character was a newline. */ 150 static int exit_status; /* Used to store the command exit status. */ 151 static int stdin_eof; /* EOF has been encountered on stderr. */ 152 static Buffer stdin_buffer; /* Buffer for stdin data. */ 153 static Buffer stdout_buffer; /* Buffer for stdout data. */ 154 static Buffer stderr_buffer; /* Buffer for stderr data. */ 155 static u_int buffer_high;/* Soft max buffer size. */ 156 static int connection_in; /* Connection to server (input). */ 157 static int connection_out; /* Connection to server (output). */ 158 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 159 static int session_closed = 0; /* In SSH2: login session closed. */ 160 161 static void client_init_dispatch(void); 162 int session_ident = -1; 163 164 /* Track escape per proto2 channel */ 165 struct escape_filter_ctx { 166 int escape_pending; 167 int escape_char; 168 }; 169 170 /* Context for channel confirmation replies */ 171 struct channel_reply_ctx { 172 const char *request_type; 173 int id, do_close; 174 }; 175 176 /* Global request success/failure callbacks */ 177 struct global_confirm { 178 TAILQ_ENTRY(global_confirm) entry; 179 global_confirm_cb *cb; 180 void *ctx; 181 int ref_count; 182 }; 183 TAILQ_HEAD(global_confirms, global_confirm); 184 static struct global_confirms global_confirms = 185 TAILQ_HEAD_INITIALIZER(global_confirms); 186 187 /*XXX*/ 188 extern Kex *xxx_kex; 189 190 void ssh_process_session2_setup(int, int, int, Buffer *); 191 192 /* Restores stdin to blocking mode. */ 193 194 static void 195 leave_non_blocking(void) 196 { 197 if (in_non_blocking_mode) { 198 unset_nonblock(fileno(stdin)); 199 in_non_blocking_mode = 0; 200 } 201 } 202 203 /* Puts stdin terminal in non-blocking mode. */ 204 205 static void 206 enter_non_blocking(void) 207 { 208 in_non_blocking_mode = 1; 209 set_nonblock(fileno(stdin)); 210 } 211 212 /* 213 * Signal handler for the window change signal (SIGWINCH). This just sets a 214 * flag indicating that the window has changed. 215 */ 216 /*ARGSUSED */ 217 static void 218 window_change_handler(int sig) 219 { 220 received_window_change_signal = 1; 221 signal(SIGWINCH, window_change_handler); 222 } 223 224 /* 225 * Signal handler for signals that cause the program to terminate. These 226 * signals must be trapped to restore terminal modes. 227 */ 228 /*ARGSUSED */ 229 static void 230 signal_handler(int sig) 231 { 232 received_signal = sig; 233 quit_pending = 1; 234 } 235 236 /* 237 * Returns current time in seconds from Jan 1, 1970 with the maximum 238 * available resolution. 239 */ 240 241 static double 242 get_current_time(void) 243 { 244 struct timeval tv; 245 gettimeofday(&tv, NULL); 246 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 247 } 248 249 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 250 void 251 client_x11_get_proto(const char *display, const char *xauth_path, 252 u_int trusted, char **_proto, char **_data) 253 { 254 char cmd[1024]; 255 char line[512]; 256 char xdisplay[512]; 257 static char proto[512], data[512]; 258 FILE *f; 259 int got_data = 0, generated = 0, do_unlink = 0, i; 260 char *xauthdir, *xauthfile; 261 struct stat st; 262 263 xauthdir = xauthfile = NULL; 264 *_proto = proto; 265 *_data = data; 266 proto[0] = data[0] = '\0'; 267 268 if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) { 269 debug("No xauth program."); 270 } else { 271 if (display == NULL) { 272 debug("x11_get_proto: DISPLAY not set"); 273 return; 274 } 275 /* 276 * Handle FamilyLocal case where $DISPLAY does 277 * not match an authorization entry. For this we 278 * just try "xauth list unix:displaynum.screennum". 279 * XXX: "localhost" match to determine FamilyLocal 280 * is not perfect. 281 */ 282 if (strncmp(display, "localhost:", 10) == 0) { 283 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 284 display + 10); 285 display = xdisplay; 286 } 287 if (trusted == 0) { 288 xauthdir = xmalloc(MAXPATHLEN); 289 xauthfile = xmalloc(MAXPATHLEN); 290 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 291 if (mkdtemp(xauthdir) != NULL) { 292 do_unlink = 1; 293 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 294 xauthdir); 295 snprintf(cmd, sizeof(cmd), 296 "%s -f %s generate %s " SSH_X11_PROTO 297 " untrusted timeout 1200 2>" _PATH_DEVNULL, 298 xauth_path, xauthfile, display); 299 debug2("x11_get_proto: %s", cmd); 300 if (system(cmd) == 0) 301 generated = 1; 302 } 303 } 304 305 /* 306 * When in untrusted mode, we read the cookie only if it was 307 * successfully generated as an untrusted one in the step 308 * above. 309 */ 310 if (trusted || generated) { 311 snprintf(cmd, sizeof(cmd), 312 "%s %s%s list %s 2>" _PATH_DEVNULL, 313 xauth_path, 314 generated ? "-f " : "" , 315 generated ? xauthfile : "", 316 display); 317 debug2("x11_get_proto: %s", cmd); 318 f = popen(cmd, "r"); 319 if (f && fgets(line, sizeof(line), f) && 320 sscanf(line, "%*s %511s %511s", proto, data) == 2) 321 got_data = 1; 322 if (f) 323 pclose(f); 324 } else 325 error("Warning: untrusted X11 forwarding setup failed: " 326 "xauth key data not generated"); 327 } 328 329 if (do_unlink) { 330 unlink(xauthfile); 331 rmdir(xauthdir); 332 } 333 if (xauthdir) 334 xfree(xauthdir); 335 if (xauthfile) 336 xfree(xauthfile); 337 338 /* 339 * If we didn't get authentication data, just make up some 340 * data. The forwarding code will check the validity of the 341 * response anyway, and substitute this data. The X11 342 * server, however, will ignore this fake data and use 343 * whatever authentication mechanisms it was using otherwise 344 * for the local connection. 345 */ 346 if (!got_data) { 347 u_int32_t rnd = 0; 348 349 logit("Warning: No xauth data; " 350 "using fake authentication data for X11 forwarding."); 351 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 352 for (i = 0; i < 16; i++) { 353 if (i % 4 == 0) 354 rnd = arc4random(); 355 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 356 rnd & 0xff); 357 rnd >>= 8; 358 } 359 } 360 } 361 362 /* 363 * This is called when the interactive is entered. This checks if there is 364 * an EOF coming on stdin. We must check this explicitly, as select() does 365 * not appear to wake up when redirecting from /dev/null. 366 */ 367 368 static void 369 client_check_initial_eof_on_stdin(void) 370 { 371 int len; 372 char buf[1]; 373 374 /* 375 * If standard input is to be "redirected from /dev/null", we simply 376 * mark that we have seen an EOF and send an EOF message to the 377 * server. Otherwise, we try to read a single character; it appears 378 * that for some files, such /dev/null, select() never wakes up for 379 * read for this descriptor, which means that we never get EOF. This 380 * way we will get the EOF if stdin comes from /dev/null or similar. 381 */ 382 if (stdin_null_flag) { 383 /* Fake EOF on stdin. */ 384 debug("Sending eof."); 385 stdin_eof = 1; 386 packet_start(SSH_CMSG_EOF); 387 packet_send(); 388 } else { 389 enter_non_blocking(); 390 391 /* Check for immediate EOF on stdin. */ 392 len = read(fileno(stdin), buf, 1); 393 if (len == 0) { 394 /* 395 * EOF. Record that we have seen it and send 396 * EOF to server. 397 */ 398 debug("Sending eof."); 399 stdin_eof = 1; 400 packet_start(SSH_CMSG_EOF); 401 packet_send(); 402 } else if (len > 0) { 403 /* 404 * Got data. We must store the data in the buffer, 405 * and also process it as an escape character if 406 * appropriate. 407 */ 408 if ((u_char) buf[0] == escape_char1) 409 escape_pending1 = 1; 410 else 411 buffer_append(&stdin_buffer, buf, 1); 412 } 413 leave_non_blocking(); 414 } 415 } 416 417 418 /* 419 * Make packets from buffered stdin data, and buffer them for sending to the 420 * connection. 421 */ 422 423 static void 424 client_make_packets_from_stdin_data(void) 425 { 426 u_int len; 427 428 /* Send buffered stdin data to the server. */ 429 while (buffer_len(&stdin_buffer) > 0 && 430 packet_not_very_much_data_to_write()) { 431 len = buffer_len(&stdin_buffer); 432 /* Keep the packets at reasonable size. */ 433 if (len > packet_get_maxsize()) 434 len = packet_get_maxsize(); 435 packet_start(SSH_CMSG_STDIN_DATA); 436 packet_put_string(buffer_ptr(&stdin_buffer), len); 437 packet_send(); 438 buffer_consume(&stdin_buffer, len); 439 /* If we have a pending EOF, send it now. */ 440 if (stdin_eof && buffer_len(&stdin_buffer) == 0) { 441 packet_start(SSH_CMSG_EOF); 442 packet_send(); 443 } 444 } 445 } 446 447 /* 448 * Checks if the client window has changed, and sends a packet about it to 449 * the server if so. The actual change is detected elsewhere (by a software 450 * interrupt on Unix); this just checks the flag and sends a message if 451 * appropriate. 452 */ 453 454 static void 455 client_check_window_change(void) 456 { 457 struct winsize ws; 458 459 if (! received_window_change_signal) 460 return; 461 /** XXX race */ 462 received_window_change_signal = 0; 463 464 debug2("client_check_window_change: changed"); 465 466 if (compat20) { 467 channel_send_window_changes(); 468 } else { 469 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 470 return; 471 packet_start(SSH_CMSG_WINDOW_SIZE); 472 packet_put_int((u_int)ws.ws_row); 473 packet_put_int((u_int)ws.ws_col); 474 packet_put_int((u_int)ws.ws_xpixel); 475 packet_put_int((u_int)ws.ws_ypixel); 476 packet_send(); 477 } 478 } 479 480 static void 481 client_global_request_reply(int type, u_int32_t seq, void *ctxt) 482 { 483 struct global_confirm *gc; 484 485 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 486 return; 487 if (gc->cb != NULL) 488 gc->cb(type, seq, gc->ctx); 489 if (--gc->ref_count <= 0) { 490 TAILQ_REMOVE(&global_confirms, gc, entry); 491 bzero(gc, sizeof(*gc)); 492 xfree(gc); 493 } 494 495 packet_set_alive_timeouts(0); 496 } 497 498 static void 499 server_alive_check(void) 500 { 501 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 502 logit("Timeout, server not responding."); 503 cleanup_exit(255); 504 } 505 packet_start(SSH2_MSG_GLOBAL_REQUEST); 506 packet_put_cstring("keepalive@openssh.com"); 507 packet_put_char(1); /* boolean: want reply */ 508 packet_send(); 509 /* Insert an empty placeholder to maintain ordering */ 510 client_register_global_confirm(NULL, NULL); 511 } 512 513 /* 514 * Waits until the client can do something (some data becomes available on 515 * one of the file descriptors). 516 */ 517 static void 518 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 519 int *maxfdp, u_int *nallocp, int rekeying) 520 { 521 struct timeval tv, *tvp; 522 int ret; 523 524 /* Add any selections by the channel mechanism. */ 525 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); 526 527 if (!compat20) { 528 /* Read from the connection, unless our buffers are full. */ 529 if (buffer_len(&stdout_buffer) < buffer_high && 530 buffer_len(&stderr_buffer) < buffer_high && 531 channel_not_very_much_buffered_data()) 532 FD_SET(connection_in, *readsetp); 533 /* 534 * Read from stdin, unless we have seen EOF or have very much 535 * buffered data to send to the server. 536 */ 537 if (!stdin_eof && packet_not_very_much_data_to_write()) 538 FD_SET(fileno(stdin), *readsetp); 539 540 /* Select stdout/stderr if have data in buffer. */ 541 if (buffer_len(&stdout_buffer) > 0) 542 FD_SET(fileno(stdout), *writesetp); 543 if (buffer_len(&stderr_buffer) > 0) 544 FD_SET(fileno(stderr), *writesetp); 545 } else { 546 /* channel_prepare_select could have closed the last channel */ 547 if (session_closed && !channel_still_open() && 548 !packet_have_data_to_write()) { 549 /* clear mask since we did not call select() */ 550 memset(*readsetp, 0, *nallocp); 551 memset(*writesetp, 0, *nallocp); 552 return; 553 } else { 554 FD_SET(connection_in, *readsetp); 555 } 556 } 557 558 /* Select server connection if have data to write to the server. */ 559 if (packet_have_data_to_write()) 560 FD_SET(connection_out, *writesetp); 561 562 if (muxserver_sock != -1) 563 FD_SET(muxserver_sock, *readsetp); 564 565 /* 566 * Wait for something to happen. This will suspend the process until 567 * some selected descriptor can be read, written, or has some other 568 * event pending. 569 */ 570 571 if (options.server_alive_interval == 0 || !compat20) 572 tvp = NULL; 573 else { 574 tv.tv_sec = options.server_alive_interval; 575 tv.tv_usec = 0; 576 tvp = &tv; 577 } 578 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 579 if (ret < 0) { 580 char buf[100]; 581 582 /* 583 * We have to clear the select masks, because we return. 584 * We have to return, because the mainloop checks for the flags 585 * set by the signal handlers. 586 */ 587 memset(*readsetp, 0, *nallocp); 588 memset(*writesetp, 0, *nallocp); 589 590 if (errno == EINTR) 591 return; 592 /* Note: we might still have data in the buffers. */ 593 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 594 buffer_append(&stderr_buffer, buf, strlen(buf)); 595 quit_pending = 1; 596 } else if (ret == 0) 597 server_alive_check(); 598 } 599 600 static void 601 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 602 { 603 /* Flush stdout and stderr buffers. */ 604 if (buffer_len(bout) > 0) 605 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 606 buffer_len(bout)); 607 if (buffer_len(berr) > 0) 608 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 609 buffer_len(berr)); 610 611 leave_raw_mode(); 612 613 /* 614 * Free (and clear) the buffer to reduce the amount of data that gets 615 * written to swap. 616 */ 617 buffer_free(bin); 618 buffer_free(bout); 619 buffer_free(berr); 620 621 /* Send the suspend signal to the program itself. */ 622 kill(getpid(), SIGTSTP); 623 624 /* Reset window sizes in case they have changed */ 625 received_window_change_signal = 1; 626 627 /* OK, we have been continued by the user. Reinitialize buffers. */ 628 buffer_init(bin); 629 buffer_init(bout); 630 buffer_init(berr); 631 632 enter_raw_mode(); 633 } 634 635 static void 636 client_process_net_input(fd_set *readset) 637 { 638 int len, cont = 0; 639 char buf[SSH_IOBUFSZ]; 640 641 /* 642 * Read input from the server, and add any such data to the buffer of 643 * the packet subsystem. 644 */ 645 if (FD_ISSET(connection_in, readset)) { 646 /* Read as much as possible. */ 647 len = roaming_read(connection_in, buf, sizeof(buf), &cont); 648 if (len == 0 && cont == 0) { 649 /* 650 * Received EOF. The remote host has closed the 651 * connection. 652 */ 653 snprintf(buf, sizeof buf, 654 "Connection to %.300s closed by remote host.\r\n", 655 host); 656 buffer_append(&stderr_buffer, buf, strlen(buf)); 657 quit_pending = 1; 658 return; 659 } 660 /* 661 * There is a kernel bug on Solaris that causes select to 662 * sometimes wake up even though there is no data available. 663 */ 664 if (len < 0 && 665 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) 666 len = 0; 667 668 if (len < 0) { 669 /* 670 * An error has encountered. Perhaps there is a 671 * network problem. 672 */ 673 snprintf(buf, sizeof buf, 674 "Read from remote host %.300s: %.100s\r\n", 675 host, strerror(errno)); 676 buffer_append(&stderr_buffer, buf, strlen(buf)); 677 quit_pending = 1; 678 return; 679 } 680 packet_process_incoming(buf, len); 681 } 682 } 683 684 static void 685 client_status_confirm(int type, Channel *c, void *ctx) 686 { 687 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 688 char errmsg[256]; 689 int tochan; 690 691 /* XXX supress on mux _client_ quietmode */ 692 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 693 c->ctl_fd != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 694 695 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 696 debug2("%s request accepted on channel %d", 697 cr->request_type, c->self); 698 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 699 if (tochan) { 700 snprintf(errmsg, sizeof(errmsg), 701 "%s request failed\r\n", cr->request_type); 702 } else { 703 snprintf(errmsg, sizeof(errmsg), 704 "%s request failed on channel %d", 705 cr->request_type, c->self); 706 } 707 /* If error occurred on primary session channel, then exit */ 708 if (cr->do_close && c->self == session_ident) 709 fatal("%s", errmsg); 710 /* If error occurred on mux client, append to their stderr */ 711 if (tochan) 712 buffer_append(&c->extended, errmsg, strlen(errmsg)); 713 else 714 error("%s", errmsg); 715 if (cr->do_close) { 716 chan_read_failed(c); 717 chan_write_failed(c); 718 } 719 } 720 xfree(cr); 721 } 722 723 static void 724 client_abandon_status_confirm(Channel *c, void *ctx) 725 { 726 xfree(ctx); 727 } 728 729 static void 730 client_expect_confirm(int id, const char *request, int do_close) 731 { 732 struct channel_reply_ctx *cr = xmalloc(sizeof(*cr)); 733 734 cr->request_type = request; 735 cr->do_close = do_close; 736 737 channel_register_status_confirm(id, client_status_confirm, 738 client_abandon_status_confirm, cr); 739 } 740 741 void 742 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 743 { 744 struct global_confirm *gc, *last_gc; 745 746 /* Coalesce identical callbacks */ 747 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 748 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 749 if (++last_gc->ref_count >= INT_MAX) 750 fatal("%s: last_gc->ref_count = %d", 751 __func__, last_gc->ref_count); 752 return; 753 } 754 755 gc = xmalloc(sizeof(*gc)); 756 gc->cb = cb; 757 gc->ctx = ctx; 758 gc->ref_count = 1; 759 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 760 } 761 762 static void 763 process_cmdline(void) 764 { 765 void (*handler)(int); 766 char *s, *cmd, *cancel_host; 767 int delete = 0; 768 int local = 0, remote = 0, dynamic = 0; 769 int cancel_port; 770 Forward fwd; 771 772 bzero(&fwd, sizeof(fwd)); 773 fwd.listen_host = fwd.connect_host = NULL; 774 775 leave_raw_mode(); 776 handler = signal(SIGINT, SIG_IGN); 777 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 778 if (s == NULL) 779 goto out; 780 while (isspace(*s)) 781 s++; 782 if (*s == '-') 783 s++; /* Skip cmdline '-', if any */ 784 if (*s == '\0') 785 goto out; 786 787 if (*s == 'h' || *s == 'H' || *s == '?') { 788 logit("Commands:"); 789 logit(" -L[bind_address:]port:host:hostport " 790 "Request local forward"); 791 logit(" -R[bind_address:]port:host:hostport " 792 "Request remote forward"); 793 logit(" -D[bind_address:]port " 794 "Request dynamic forward"); 795 logit(" -KR[bind_address:]port " 796 "Cancel remote forward"); 797 if (!options.permit_local_command) 798 goto out; 799 logit(" !args " 800 "Execute local command"); 801 goto out; 802 } 803 804 if (*s == '!' && options.permit_local_command) { 805 s++; 806 ssh_local_cmd(s); 807 goto out; 808 } 809 810 if (*s == 'K') { 811 delete = 1; 812 s++; 813 } 814 if (*s == 'L') 815 local = 1; 816 else if (*s == 'R') 817 remote = 1; 818 else if (*s == 'D') 819 dynamic = 1; 820 else { 821 logit("Invalid command."); 822 goto out; 823 } 824 825 if ((local || dynamic) && delete) { 826 logit("Not supported."); 827 goto out; 828 } 829 if (remote && delete && !compat20) { 830 logit("Not supported for SSH protocol version 1."); 831 goto out; 832 } 833 834 while (isspace(*++s)) 835 ; 836 837 if (delete) { 838 cancel_port = 0; 839 cancel_host = hpdelim(&s); /* may be NULL */ 840 if (s != NULL) { 841 cancel_port = a2port(s); 842 cancel_host = cleanhostname(cancel_host); 843 } else { 844 cancel_port = a2port(cancel_host); 845 cancel_host = NULL; 846 } 847 if (cancel_port <= 0) { 848 logit("Bad forwarding close port"); 849 goto out; 850 } 851 channel_request_rforward_cancel(cancel_host, cancel_port); 852 } else { 853 if (!parse_forward(&fwd, s, dynamic, remote)) { 854 logit("Bad forwarding specification."); 855 goto out; 856 } 857 if (local || dynamic) { 858 if (channel_setup_local_fwd_listener(fwd.listen_host, 859 fwd.listen_port, fwd.connect_host, 860 fwd.connect_port, options.gateway_ports) < 0) { 861 logit("Port forwarding failed."); 862 goto out; 863 } 864 } else { 865 if (channel_request_remote_forwarding(fwd.listen_host, 866 fwd.listen_port, fwd.connect_host, 867 fwd.connect_port) < 0) { 868 logit("Port forwarding failed."); 869 goto out; 870 } 871 } 872 873 logit("Forwarding port."); 874 } 875 876 out: 877 signal(SIGINT, handler); 878 enter_raw_mode(); 879 if (cmd) 880 xfree(cmd); 881 if (fwd.listen_host != NULL) 882 xfree(fwd.listen_host); 883 if (fwd.connect_host != NULL) 884 xfree(fwd.connect_host); 885 } 886 887 /* 888 * Process the characters one by one, call with c==NULL for proto1 case. 889 */ 890 static int 891 process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr, 892 char *buf, int len) 893 { 894 char string[1024]; 895 pid_t pid; 896 int bytes = 0; 897 u_int i; 898 u_char ch; 899 char *s; 900 int *escape_pendingp, escape_char; 901 struct escape_filter_ctx *efc; 902 903 if (c == NULL) { 904 escape_pendingp = &escape_pending1; 905 escape_char = escape_char1; 906 } else { 907 if (c->filter_ctx == NULL) 908 return 0; 909 efc = (struct escape_filter_ctx *)c->filter_ctx; 910 escape_pendingp = &efc->escape_pending; 911 escape_char = efc->escape_char; 912 } 913 914 if (len <= 0) 915 return (0); 916 917 for (i = 0; i < (u_int)len; i++) { 918 /* Get one character at a time. */ 919 ch = buf[i]; 920 921 if (*escape_pendingp) { 922 /* We have previously seen an escape character. */ 923 /* Clear the flag now. */ 924 *escape_pendingp = 0; 925 926 /* Process the escaped character. */ 927 switch (ch) { 928 case '.': 929 /* Terminate the connection. */ 930 snprintf(string, sizeof string, "%c.\r\n", 931 escape_char); 932 buffer_append(berr, string, strlen(string)); 933 934 if (c && c->ctl_fd != -1) { 935 chan_read_failed(c); 936 chan_write_failed(c); 937 return 0; 938 } else 939 quit_pending = 1; 940 return -1; 941 942 case 'Z' - 64: 943 /* XXX support this for mux clients */ 944 if (c && c->ctl_fd != -1) { 945 noescape: 946 snprintf(string, sizeof string, 947 "%c%c escape not available to " 948 "multiplexed sessions\r\n", 949 escape_char, ch); 950 buffer_append(berr, string, 951 strlen(string)); 952 continue; 953 } 954 /* Suspend the program. Inform the user */ 955 snprintf(string, sizeof string, 956 "%c^Z [suspend ssh]\r\n", escape_char); 957 buffer_append(berr, string, strlen(string)); 958 959 /* Restore terminal modes and suspend. */ 960 client_suspend_self(bin, bout, berr); 961 962 /* We have been continued. */ 963 continue; 964 965 case 'B': 966 if (compat20) { 967 snprintf(string, sizeof string, 968 "%cB\r\n", escape_char); 969 buffer_append(berr, string, 970 strlen(string)); 971 channel_request_start(session_ident, 972 "break", 0); 973 packet_put_int(1000); 974 packet_send(); 975 } 976 continue; 977 978 case 'R': 979 if (compat20) { 980 if (datafellows & SSH_BUG_NOREKEY) 981 logit("Server does not " 982 "support re-keying"); 983 else 984 need_rekeying = 1; 985 } 986 continue; 987 988 case '&': 989 if (c && c->ctl_fd != -1) 990 goto noescape; 991 /* 992 * Detach the program (continue to serve 993 * connections, but put in background and no 994 * more new connections). 995 */ 996 /* Restore tty modes. */ 997 leave_raw_mode(); 998 999 /* Stop listening for new connections. */ 1000 channel_stop_listening(); 1001 1002 snprintf(string, sizeof string, 1003 "%c& [backgrounded]\n", escape_char); 1004 buffer_append(berr, string, strlen(string)); 1005 1006 /* Fork into background. */ 1007 pid = fork(); 1008 if (pid < 0) { 1009 error("fork: %.100s", strerror(errno)); 1010 continue; 1011 } 1012 if (pid != 0) { /* This is the parent. */ 1013 /* The parent just exits. */ 1014 exit(0); 1015 } 1016 /* The child continues serving connections. */ 1017 if (compat20) { 1018 buffer_append(bin, "\004", 1); 1019 /* fake EOF on stdin */ 1020 return -1; 1021 } else if (!stdin_eof) { 1022 /* 1023 * Sending SSH_CMSG_EOF alone does not 1024 * always appear to be enough. So we 1025 * try to send an EOF character first. 1026 */ 1027 packet_start(SSH_CMSG_STDIN_DATA); 1028 packet_put_string("\004", 1); 1029 packet_send(); 1030 /* Close stdin. */ 1031 stdin_eof = 1; 1032 if (buffer_len(bin) == 0) { 1033 packet_start(SSH_CMSG_EOF); 1034 packet_send(); 1035 } 1036 } 1037 continue; 1038 1039 case '?': 1040 if (c && c->ctl_fd != -1) { 1041 snprintf(string, sizeof string, 1042 "%c?\r\n\ 1043 Supported escape sequences:\r\n\ 1044 %c. - terminate session\r\n\ 1045 %cB - send a BREAK to the remote system\r\n\ 1046 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1047 %c# - list forwarded connections\r\n\ 1048 %c? - this message\r\n\ 1049 %c%c - send the escape character by typing it twice\r\n\ 1050 (Note that escapes are only recognized immediately after newline.)\r\n", 1051 escape_char, escape_char, 1052 escape_char, escape_char, 1053 escape_char, escape_char, 1054 escape_char, escape_char); 1055 } else { 1056 snprintf(string, sizeof string, 1057 "%c?\r\n\ 1058 Supported escape sequences:\r\n\ 1059 %c. - terminate connection (and any multiplexed sessions)\r\n\ 1060 %cB - send a BREAK to the remote system\r\n\ 1061 %cC - open a command line\r\n\ 1062 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1063 %c^Z - suspend ssh\r\n\ 1064 %c# - list forwarded connections\r\n\ 1065 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1066 %c? - this message\r\n\ 1067 %c%c - send the escape character by typing it twice\r\n\ 1068 (Note that escapes are only recognized immediately after newline.)\r\n", 1069 escape_char, escape_char, 1070 escape_char, escape_char, 1071 escape_char, escape_char, 1072 escape_char, escape_char, 1073 escape_char, escape_char, 1074 escape_char); 1075 } 1076 buffer_append(berr, string, strlen(string)); 1077 continue; 1078 1079 case '#': 1080 snprintf(string, sizeof string, "%c#\r\n", 1081 escape_char); 1082 buffer_append(berr, string, strlen(string)); 1083 s = channel_open_message(); 1084 buffer_append(berr, s, strlen(s)); 1085 xfree(s); 1086 continue; 1087 1088 case 'C': 1089 if (c && c->ctl_fd != -1) 1090 goto noescape; 1091 process_cmdline(); 1092 continue; 1093 1094 default: 1095 if (ch != escape_char) { 1096 buffer_put_char(bin, escape_char); 1097 bytes++; 1098 } 1099 /* Escaped characters fall through here */ 1100 break; 1101 } 1102 } else { 1103 /* 1104 * The previous character was not an escape char. 1105 * Check if this is an escape. 1106 */ 1107 if (last_was_cr && ch == escape_char) { 1108 /* 1109 * It is. Set the flag and continue to 1110 * next character. 1111 */ 1112 *escape_pendingp = 1; 1113 continue; 1114 } 1115 } 1116 1117 /* 1118 * Normal character. Record whether it was a newline, 1119 * and append it to the buffer. 1120 */ 1121 last_was_cr = (ch == '\r' || ch == '\n'); 1122 buffer_put_char(bin, ch); 1123 bytes++; 1124 } 1125 return bytes; 1126 } 1127 1128 static void 1129 client_process_input(fd_set *readset) 1130 { 1131 int len; 1132 char buf[SSH_IOBUFSZ]; 1133 1134 /* Read input from stdin. */ 1135 if (FD_ISSET(fileno(stdin), readset)) { 1136 /* Read as much as possible. */ 1137 len = read(fileno(stdin), buf, sizeof(buf)); 1138 if (len < 0 && 1139 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) 1140 return; /* we'll try again later */ 1141 if (len <= 0) { 1142 /* 1143 * Received EOF or error. They are treated 1144 * similarly, except that an error message is printed 1145 * if it was an error condition. 1146 */ 1147 if (len < 0) { 1148 snprintf(buf, sizeof buf, "read: %.100s\r\n", 1149 strerror(errno)); 1150 buffer_append(&stderr_buffer, buf, strlen(buf)); 1151 } 1152 /* Mark that we have seen EOF. */ 1153 stdin_eof = 1; 1154 /* 1155 * Send an EOF message to the server unless there is 1156 * data in the buffer. If there is data in the 1157 * buffer, no message will be sent now. Code 1158 * elsewhere will send the EOF when the buffer 1159 * becomes empty if stdin_eof is set. 1160 */ 1161 if (buffer_len(&stdin_buffer) == 0) { 1162 packet_start(SSH_CMSG_EOF); 1163 packet_send(); 1164 } 1165 } else if (escape_char1 == SSH_ESCAPECHAR_NONE) { 1166 /* 1167 * Normal successful read, and no escape character. 1168 * Just append the data to buffer. 1169 */ 1170 buffer_append(&stdin_buffer, buf, len); 1171 } else { 1172 /* 1173 * Normal, successful read. But we have an escape 1174 * character and have to process the characters one 1175 * by one. 1176 */ 1177 if (process_escapes(NULL, &stdin_buffer, 1178 &stdout_buffer, &stderr_buffer, buf, len) == -1) 1179 return; 1180 } 1181 } 1182 } 1183 1184 static void 1185 client_process_output(fd_set *writeset) 1186 { 1187 int len; 1188 char buf[100]; 1189 1190 /* Write buffered output to stdout. */ 1191 if (FD_ISSET(fileno(stdout), writeset)) { 1192 /* Write as much data as possible. */ 1193 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1194 buffer_len(&stdout_buffer)); 1195 if (len <= 0) { 1196 if (errno == EINTR || errno == EAGAIN || 1197 errno == EWOULDBLOCK) 1198 len = 0; 1199 else { 1200 /* 1201 * An error or EOF was encountered. Put an 1202 * error message to stderr buffer. 1203 */ 1204 snprintf(buf, sizeof buf, 1205 "write stdout: %.50s\r\n", strerror(errno)); 1206 buffer_append(&stderr_buffer, buf, strlen(buf)); 1207 quit_pending = 1; 1208 return; 1209 } 1210 } 1211 /* Consume printed data from the buffer. */ 1212 buffer_consume(&stdout_buffer, len); 1213 } 1214 /* Write buffered output to stderr. */ 1215 if (FD_ISSET(fileno(stderr), writeset)) { 1216 /* Write as much data as possible. */ 1217 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1218 buffer_len(&stderr_buffer)); 1219 if (len <= 0) { 1220 if (errno == EINTR || errno == EAGAIN || 1221 errno == EWOULDBLOCK) 1222 len = 0; 1223 else { 1224 /* 1225 * EOF or error, but can't even print 1226 * error message. 1227 */ 1228 quit_pending = 1; 1229 return; 1230 } 1231 } 1232 /* Consume printed characters from the buffer. */ 1233 buffer_consume(&stderr_buffer, len); 1234 } 1235 } 1236 1237 /* 1238 * Get packets from the connection input buffer, and process them as long as 1239 * there are packets available. 1240 * 1241 * Any unknown packets received during the actual 1242 * session cause the session to terminate. This is 1243 * intended to make debugging easier since no 1244 * confirmations are sent. Any compatible protocol 1245 * extensions must be negotiated during the 1246 * preparatory phase. 1247 */ 1248 1249 static void 1250 client_process_buffered_input_packets(void) 1251 { 1252 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, 1253 compat20 ? xxx_kex : NULL); 1254 } 1255 1256 /* scan buf[] for '~' before sending data to the peer */ 1257 1258 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1259 void * 1260 client_new_escape_filter_ctx(int escape_char) 1261 { 1262 struct escape_filter_ctx *ret; 1263 1264 ret = xmalloc(sizeof(*ret)); 1265 ret->escape_pending = 0; 1266 ret->escape_char = escape_char; 1267 return (void *)ret; 1268 } 1269 1270 /* Free the escape filter context on channel free */ 1271 void 1272 client_filter_cleanup(int cid, void *ctx) 1273 { 1274 xfree(ctx); 1275 } 1276 1277 int 1278 client_simple_escape_filter(Channel *c, char *buf, int len) 1279 { 1280 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1281 return 0; 1282 1283 return process_escapes(c, &c->input, &c->output, &c->extended, 1284 buf, len); 1285 } 1286 1287 static void 1288 client_channel_closed(int id, void *arg) 1289 { 1290 channel_cancel_cleanup(id); 1291 session_closed = 1; 1292 leave_raw_mode(); 1293 } 1294 1295 /* 1296 * Implements the interactive session with the server. This is called after 1297 * the user has been authenticated, and a command has been started on the 1298 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1299 * used as an escape character for terminating or suspending the session. 1300 */ 1301 1302 int 1303 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1304 { 1305 fd_set *readset = NULL, *writeset = NULL; 1306 double start_time, total_time; 1307 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1308 u_int64_t ibytes, obytes; 1309 u_int nalloc = 0; 1310 char buf[100]; 1311 1312 debug("Entering interactive session."); 1313 1314 start_time = get_current_time(); 1315 1316 /* Initialize variables. */ 1317 escape_pending1 = 0; 1318 last_was_cr = 1; 1319 exit_status = -1; 1320 stdin_eof = 0; 1321 buffer_high = 64 * 1024; 1322 connection_in = packet_get_connection_in(); 1323 connection_out = packet_get_connection_out(); 1324 max_fd = MAX(connection_in, connection_out); 1325 if (muxserver_sock != -1) 1326 max_fd = MAX(max_fd, muxserver_sock); 1327 1328 if (!compat20) { 1329 /* enable nonblocking unless tty */ 1330 if (!isatty(fileno(stdin))) 1331 set_nonblock(fileno(stdin)); 1332 if (!isatty(fileno(stdout))) 1333 set_nonblock(fileno(stdout)); 1334 if (!isatty(fileno(stderr))) 1335 set_nonblock(fileno(stderr)); 1336 max_fd = MAX(max_fd, fileno(stdin)); 1337 max_fd = MAX(max_fd, fileno(stdout)); 1338 max_fd = MAX(max_fd, fileno(stderr)); 1339 } 1340 quit_pending = 0; 1341 escape_char1 = escape_char_arg; 1342 1343 /* Initialize buffers. */ 1344 buffer_init(&stdin_buffer); 1345 buffer_init(&stdout_buffer); 1346 buffer_init(&stderr_buffer); 1347 1348 client_init_dispatch(); 1349 1350 /* 1351 * Set signal handlers, (e.g. to restore non-blocking mode) 1352 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1353 */ 1354 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1355 signal(SIGHUP, signal_handler); 1356 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1357 signal(SIGINT, signal_handler); 1358 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1359 signal(SIGQUIT, signal_handler); 1360 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1361 signal(SIGTERM, signal_handler); 1362 signal(SIGWINCH, window_change_handler); 1363 1364 if (have_pty) 1365 enter_raw_mode(); 1366 1367 if (compat20) { 1368 session_ident = ssh2_chan_id; 1369 if (escape_char_arg != SSH_ESCAPECHAR_NONE) 1370 channel_register_filter(session_ident, 1371 client_simple_escape_filter, NULL, 1372 client_filter_cleanup, 1373 client_new_escape_filter_ctx(escape_char_arg)); 1374 if (session_ident != -1) 1375 channel_register_cleanup(session_ident, 1376 client_channel_closed, 0); 1377 } else { 1378 /* Check if we should immediately send eof on stdin. */ 1379 client_check_initial_eof_on_stdin(); 1380 } 1381 1382 /* Main loop of the client for the interactive session mode. */ 1383 while (!quit_pending) { 1384 1385 /* Process buffered packets sent by the server. */ 1386 client_process_buffered_input_packets(); 1387 1388 if (compat20 && session_closed && !channel_still_open()) 1389 break; 1390 1391 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1392 1393 if (rekeying) { 1394 debug("rekeying in progress"); 1395 } else { 1396 /* 1397 * Make packets of buffered stdin data, and buffer 1398 * them for sending to the server. 1399 */ 1400 if (!compat20) 1401 client_make_packets_from_stdin_data(); 1402 1403 /* 1404 * Make packets from buffered channel data, and 1405 * enqueue them for sending to the server. 1406 */ 1407 if (packet_not_very_much_data_to_write()) 1408 channel_output_poll(); 1409 1410 /* 1411 * Check if the window size has changed, and buffer a 1412 * message about it to the server if so. 1413 */ 1414 client_check_window_change(); 1415 1416 if (quit_pending) 1417 break; 1418 } 1419 /* 1420 * Wait until we have something to do (something becomes 1421 * available on one of the descriptors). 1422 */ 1423 max_fd2 = max_fd; 1424 client_wait_until_can_do_something(&readset, &writeset, 1425 &max_fd2, &nalloc, rekeying); 1426 1427 if (quit_pending) 1428 break; 1429 1430 /* Do channel operations unless rekeying in progress. */ 1431 if (!rekeying) { 1432 channel_after_select(readset, writeset); 1433 if (need_rekeying || packet_need_rekeying()) { 1434 debug("need rekeying"); 1435 xxx_kex->done = 0; 1436 kex_send_kexinit(xxx_kex); 1437 need_rekeying = 0; 1438 } 1439 } 1440 1441 /* Buffer input from the connection. */ 1442 client_process_net_input(readset); 1443 1444 /* Accept control connections. */ 1445 if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) { 1446 if (muxserver_accept_control()) 1447 quit_pending = 1; 1448 } 1449 1450 if (quit_pending) 1451 break; 1452 1453 if (!compat20) { 1454 /* Buffer data from stdin */ 1455 client_process_input(readset); 1456 /* 1457 * Process output to stdout and stderr. Output to 1458 * the connection is processed elsewhere (above). 1459 */ 1460 client_process_output(writeset); 1461 } 1462 1463 /* 1464 * Send as much buffered packet data as possible to the 1465 * sender. 1466 */ 1467 if (FD_ISSET(connection_out, writeset)) 1468 packet_write_poll(); 1469 } 1470 if (readset) 1471 xfree(readset); 1472 if (writeset) 1473 xfree(writeset); 1474 1475 /* Terminate the session. */ 1476 1477 /* Stop watching for window change. */ 1478 signal(SIGWINCH, SIG_DFL); 1479 1480 if (compat20) { 1481 packet_start(SSH2_MSG_DISCONNECT); 1482 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1483 packet_put_cstring("disconnected by user"); 1484 packet_send(); 1485 packet_write_wait(); 1486 } 1487 1488 channel_free_all(); 1489 1490 if (have_pty) 1491 leave_raw_mode(); 1492 1493 /* restore blocking io */ 1494 if (!isatty(fileno(stdin))) 1495 unset_nonblock(fileno(stdin)); 1496 if (!isatty(fileno(stdout))) 1497 unset_nonblock(fileno(stdout)); 1498 if (!isatty(fileno(stderr))) 1499 unset_nonblock(fileno(stderr)); 1500 1501 /* 1502 * If there was no shell or command requested, there will be no remote 1503 * exit status to be returned. In that case, clear error code if the 1504 * connection was deliberately terminated at this end. 1505 */ 1506 if (no_shell_flag && received_signal == SIGTERM) { 1507 received_signal = 0; 1508 exit_status = 0; 1509 } 1510 1511 if (received_signal) 1512 fatal("Killed by signal %d.", (int) received_signal); 1513 1514 /* 1515 * In interactive mode (with pseudo tty) display a message indicating 1516 * that the connection has been closed. 1517 */ 1518 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1519 snprintf(buf, sizeof buf, 1520 "Connection to %.64s closed.\r\n", host); 1521 buffer_append(&stderr_buffer, buf, strlen(buf)); 1522 } 1523 1524 /* Output any buffered data for stdout. */ 1525 while (buffer_len(&stdout_buffer) > 0) { 1526 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1527 buffer_len(&stdout_buffer)); 1528 if (len <= 0) { 1529 error("Write failed flushing stdout buffer."); 1530 break; 1531 } 1532 buffer_consume(&stdout_buffer, len); 1533 } 1534 1535 /* Output any buffered data for stderr. */ 1536 while (buffer_len(&stderr_buffer) > 0) { 1537 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1538 buffer_len(&stderr_buffer)); 1539 if (len <= 0) { 1540 error("Write failed flushing stderr buffer."); 1541 break; 1542 } 1543 buffer_consume(&stderr_buffer, len); 1544 } 1545 1546 /* Clear and free any buffers. */ 1547 memset(buf, 0, sizeof(buf)); 1548 buffer_free(&stdin_buffer); 1549 buffer_free(&stdout_buffer); 1550 buffer_free(&stderr_buffer); 1551 1552 /* Report bytes transferred, and transfer rates. */ 1553 total_time = get_current_time() - start_time; 1554 packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); 1555 packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); 1556 verbose("Transferred: sent %ju, received %ju bytes, in %.1f seconds", 1557 (uintmax_t)obytes, (uintmax_t)ibytes, total_time); 1558 if (total_time > 0) 1559 verbose("Bytes per second: sent %.1f, received %.1f", 1560 obytes / total_time, ibytes / total_time); 1561 /* Return the exit status of the program. */ 1562 debug("Exit status %d", exit_status); 1563 return exit_status; 1564 } 1565 1566 /*********/ 1567 1568 static void 1569 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1570 { 1571 u_int data_len; 1572 char *data = packet_get_string(&data_len); 1573 packet_check_eom(); 1574 buffer_append(&stdout_buffer, data, data_len); 1575 memset(data, 0, data_len); 1576 xfree(data); 1577 } 1578 static void 1579 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1580 { 1581 u_int data_len; 1582 char *data = packet_get_string(&data_len); 1583 packet_check_eom(); 1584 buffer_append(&stderr_buffer, data, data_len); 1585 memset(data, 0, data_len); 1586 xfree(data); 1587 } 1588 static void 1589 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1590 { 1591 exit_status = packet_get_int(); 1592 packet_check_eom(); 1593 /* Acknowledge the exit. */ 1594 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1595 packet_send(); 1596 /* 1597 * Must wait for packet to be sent since we are 1598 * exiting the loop. 1599 */ 1600 packet_write_wait(); 1601 /* Flag that we want to exit. */ 1602 quit_pending = 1; 1603 } 1604 static void 1605 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1606 { 1607 Channel *c = NULL; 1608 int remote_id, sock; 1609 1610 /* Read the remote channel number from the message. */ 1611 remote_id = packet_get_int(); 1612 packet_check_eom(); 1613 1614 /* 1615 * Get a connection to the local authentication agent (this may again 1616 * get forwarded). 1617 */ 1618 sock = ssh_get_authentication_socket(); 1619 1620 /* 1621 * If we could not connect the agent, send an error message back to 1622 * the server. This should never happen unless the agent dies, 1623 * because authentication forwarding is only enabled if we have an 1624 * agent. 1625 */ 1626 if (sock >= 0) { 1627 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1628 -1, 0, 0, 0, "authentication agent connection", 1); 1629 c->remote_id = remote_id; 1630 c->force_drain = 1; 1631 } 1632 if (c == NULL) { 1633 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1634 packet_put_int(remote_id); 1635 } else { 1636 /* Send a confirmation to the remote host. */ 1637 debug("Forwarding authentication connection."); 1638 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1639 packet_put_int(remote_id); 1640 packet_put_int(c->self); 1641 } 1642 packet_send(); 1643 } 1644 1645 static Channel * 1646 client_request_forwarded_tcpip(const char *request_type, int rchan) 1647 { 1648 Channel *c = NULL; 1649 char *listen_address, *originator_address; 1650 u_short listen_port, originator_port; 1651 1652 /* Get rest of the packet */ 1653 listen_address = packet_get_string(NULL); 1654 listen_port = packet_get_int(); 1655 originator_address = packet_get_string(NULL); 1656 originator_port = packet_get_int(); 1657 packet_check_eom(); 1658 1659 debug("client_request_forwarded_tcpip: listen %s port %d, " 1660 "originator %s port %d", listen_address, listen_port, 1661 originator_address, originator_port); 1662 1663 c = channel_connect_by_listen_address(listen_port, 1664 "forwarded-tcpip", originator_address); 1665 1666 xfree(originator_address); 1667 xfree(listen_address); 1668 return c; 1669 } 1670 1671 static Channel * 1672 client_request_x11(const char *request_type, int rchan) 1673 { 1674 Channel *c = NULL; 1675 char *originator; 1676 u_short originator_port; 1677 int sock; 1678 1679 if (!options.forward_x11) { 1680 error("Warning: ssh server tried X11 forwarding."); 1681 error("Warning: this is probably a break-in attempt by a " 1682 "malicious server."); 1683 return NULL; 1684 } 1685 originator = packet_get_string(NULL); 1686 if (datafellows & SSH_BUG_X11FWD) { 1687 debug2("buggy server: x11 request w/o originator_port"); 1688 originator_port = 0; 1689 } else { 1690 originator_port = packet_get_int(); 1691 } 1692 packet_check_eom(); 1693 /* XXX check permission */ 1694 debug("client_request_x11: request from %s %d", originator, 1695 originator_port); 1696 xfree(originator); 1697 sock = x11_connect_display(); 1698 if (sock < 0) 1699 return NULL; 1700 /* again is this really necessary for X11? */ 1701 if (options.hpn_disabled) 1702 c = channel_new("x11", 1703 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1704 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1705 else 1706 c = channel_new("x11", 1707 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1708 options.hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1709 c->force_drain = 1; 1710 return c; 1711 } 1712 1713 static Channel * 1714 client_request_agent(const char *request_type, int rchan) 1715 { 1716 Channel *c = NULL; 1717 int sock; 1718 1719 if (!options.forward_agent) { 1720 error("Warning: ssh server tried agent forwarding."); 1721 error("Warning: this is probably a break-in attempt by a " 1722 "malicious server."); 1723 return NULL; 1724 } 1725 sock = ssh_get_authentication_socket(); 1726 if (sock < 0) 1727 return NULL; 1728 if (options.hpn_disabled) 1729 c = channel_new("authentication agent connection", 1730 SSH_CHANNEL_OPEN, sock, sock, -1, 1731 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1732 "authentication agent connection", 1); 1733 else 1734 c = channel_new("authentication agent connection", 1735 SSH_CHANNEL_OPEN, sock, sock, -1, 1736 options.hpn_buffer_size, options.hpn_buffer_size, 0, 1737 "authentication agent connection", 1); 1738 c->force_drain = 1; 1739 return c; 1740 } 1741 1742 int 1743 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun) 1744 { 1745 Channel *c; 1746 int fd; 1747 1748 if (tun_mode == SSH_TUNMODE_NO) 1749 return 0; 1750 1751 if (!compat20) { 1752 error("Tunnel forwarding is not supported for protocol 1"); 1753 return -1; 1754 } 1755 1756 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1757 1758 /* Open local tunnel device */ 1759 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1760 error("Tunnel device open failed."); 1761 return -1; 1762 } 1763 1764 if(options.hpn_disabled) 1765 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1766 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1767 0, "tun", 1); 1768 else 1769 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1770 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 1771 0, "tun", 1); 1772 c->datagram = 1; 1773 1774 1775 1776 #if defined(SSH_TUN_FILTER) 1777 if (options.tun_open == SSH_TUNMODE_POINTOPOINT) 1778 channel_register_filter(c->self, sys_tun_infilter, 1779 sys_tun_outfilter, NULL, NULL); 1780 #endif 1781 1782 packet_start(SSH2_MSG_CHANNEL_OPEN); 1783 packet_put_cstring("tun@openssh.com"); 1784 packet_put_int(c->self); 1785 packet_put_int(c->local_window_max); 1786 packet_put_int(c->local_maxpacket); 1787 packet_put_int(tun_mode); 1788 packet_put_int(remote_tun); 1789 packet_send(); 1790 1791 return 0; 1792 } 1793 1794 /* XXXX move to generic input handler */ 1795 static void 1796 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1797 { 1798 Channel *c = NULL; 1799 char *ctype; 1800 int rchan; 1801 u_int rmaxpack, rwindow, len; 1802 1803 ctype = packet_get_string(&len); 1804 rchan = packet_get_int(); 1805 rwindow = packet_get_int(); 1806 rmaxpack = packet_get_int(); 1807 1808 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1809 ctype, rchan, rwindow, rmaxpack); 1810 1811 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1812 c = client_request_forwarded_tcpip(ctype, rchan); 1813 } else if (strcmp(ctype, "x11") == 0) { 1814 c = client_request_x11(ctype, rchan); 1815 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1816 c = client_request_agent(ctype, rchan); 1817 } 1818 /* XXX duplicate : */ 1819 if (c != NULL) { 1820 debug("confirm %s", ctype); 1821 c->remote_id = rchan; 1822 c->remote_window = rwindow; 1823 c->remote_maxpacket = rmaxpack; 1824 if (c->type != SSH_CHANNEL_CONNECTING) { 1825 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1826 packet_put_int(c->remote_id); 1827 packet_put_int(c->self); 1828 packet_put_int(c->local_window); 1829 packet_put_int(c->local_maxpacket); 1830 packet_send(); 1831 } 1832 } else { 1833 debug("failure %s", ctype); 1834 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1835 packet_put_int(rchan); 1836 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1837 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1838 packet_put_cstring("open failed"); 1839 packet_put_cstring(""); 1840 } 1841 packet_send(); 1842 } 1843 xfree(ctype); 1844 } 1845 static void 1846 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1847 { 1848 Channel *c = NULL; 1849 int exitval, id, reply, success = 0; 1850 char *rtype; 1851 1852 id = packet_get_int(); 1853 rtype = packet_get_string(NULL); 1854 reply = packet_get_char(); 1855 1856 debug("client_input_channel_req: channel %d rtype %s reply %d", 1857 id, rtype, reply); 1858 1859 if (id == -1) { 1860 error("client_input_channel_req: request for channel -1"); 1861 } else if ((c = channel_lookup(id)) == NULL) { 1862 error("client_input_channel_req: channel %d: " 1863 "unknown channel", id); 1864 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1865 packet_check_eom(); 1866 chan_rcvd_eow(c); 1867 } else if (strcmp(rtype, "exit-status") == 0) { 1868 exitval = packet_get_int(); 1869 if (id == session_ident) { 1870 success = 1; 1871 exit_status = exitval; 1872 } else if (c->ctl_fd == -1) { 1873 error("client_input_channel_req: unexpected channel %d", 1874 session_ident); 1875 } else { 1876 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1877 success = 1; 1878 } 1879 packet_check_eom(); 1880 } 1881 if (reply) { 1882 packet_start(success ? 1883 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1884 packet_put_int(c->remote_id); 1885 packet_send(); 1886 } 1887 xfree(rtype); 1888 } 1889 static void 1890 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1891 { 1892 char *rtype; 1893 int want_reply; 1894 int success = 0; 1895 1896 rtype = packet_get_string(NULL); 1897 want_reply = packet_get_char(); 1898 debug("client_input_global_request: rtype %s want_reply %d", 1899 rtype, want_reply); 1900 if (want_reply) { 1901 packet_start(success ? 1902 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1903 packet_send(); 1904 packet_write_wait(); 1905 } 1906 xfree(rtype); 1907 } 1908 1909 void 1910 client_session2_setup(int id, int want_tty, int want_subsystem, 1911 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 1912 { 1913 int len; 1914 Channel *c = NULL; 1915 1916 debug2("%s: id %d", __func__, id); 1917 1918 if ((c = channel_lookup(id)) == NULL) 1919 fatal("client_session2_setup: channel %d: unknown channel", id); 1920 1921 if (want_tty) { 1922 struct winsize ws; 1923 1924 /* Store window size in the packet. */ 1925 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1926 memset(&ws, 0, sizeof(ws)); 1927 1928 channel_request_start(id, "pty-req", 1); 1929 client_expect_confirm(id, "PTY allocation", 0); 1930 packet_put_cstring(term != NULL ? term : ""); 1931 packet_put_int((u_int)ws.ws_col); 1932 packet_put_int((u_int)ws.ws_row); 1933 packet_put_int((u_int)ws.ws_xpixel); 1934 packet_put_int((u_int)ws.ws_ypixel); 1935 if (tiop == NULL) 1936 tiop = get_saved_tio(); 1937 tty_make_modes(-1, tiop); 1938 packet_send(); 1939 /* XXX wait for reply */ 1940 c->client_tty = 1; 1941 } 1942 1943 /* Transfer any environment variables from client to server */ 1944 if (options.num_send_env != 0 && env != NULL) { 1945 int i, j, matched; 1946 char *name, *val; 1947 1948 debug("Sending environment."); 1949 for (i = 0; env[i] != NULL; i++) { 1950 /* Split */ 1951 name = xstrdup(env[i]); 1952 if ((val = strchr(name, '=')) == NULL) { 1953 xfree(name); 1954 continue; 1955 } 1956 *val++ = '\0'; 1957 1958 matched = 0; 1959 for (j = 0; j < options.num_send_env; j++) { 1960 if (match_pattern(name, options.send_env[j])) { 1961 matched = 1; 1962 break; 1963 } 1964 } 1965 if (!matched) { 1966 debug3("Ignored env %s", name); 1967 xfree(name); 1968 continue; 1969 } 1970 1971 debug("Sending env %s = %s", name, val); 1972 channel_request_start(id, "env", 0); 1973 packet_put_cstring(name); 1974 packet_put_cstring(val); 1975 packet_send(); 1976 xfree(name); 1977 } 1978 } 1979 1980 len = buffer_len(cmd); 1981 if (len > 0) { 1982 if (len > 900) 1983 len = 900; 1984 if (want_subsystem) { 1985 debug("Sending subsystem: %.*s", 1986 len, (u_char*)buffer_ptr(cmd)); 1987 channel_request_start(id, "subsystem", 1); 1988 client_expect_confirm(id, "subsystem", 1); 1989 } else { 1990 debug("Sending command: %.*s", 1991 len, (u_char*)buffer_ptr(cmd)); 1992 channel_request_start(id, "exec", 1); 1993 client_expect_confirm(id, "exec", 1); 1994 } 1995 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1996 packet_send(); 1997 } else { 1998 channel_request_start(id, "shell", 1); 1999 client_expect_confirm(id, "shell", 1); 2000 packet_send(); 2001 } 2002 } 2003 2004 static void 2005 client_init_dispatch_20(void) 2006 { 2007 dispatch_init(&dispatch_protocol_error); 2008 2009 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2010 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2011 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2012 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2013 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2014 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2015 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2016 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2017 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2018 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2019 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2020 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2021 2022 /* rekeying */ 2023 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2024 2025 /* global request reply messages */ 2026 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2027 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2028 } 2029 2030 static void 2031 client_init_dispatch_13(void) 2032 { 2033 dispatch_init(NULL); 2034 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 2035 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 2036 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2037 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2038 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2039 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2040 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2041 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2042 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2043 2044 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2045 &client_input_agent_open : &deny_input_open); 2046 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2047 &x11_input_open : &deny_input_open); 2048 } 2049 2050 static void 2051 client_init_dispatch_15(void) 2052 { 2053 client_init_dispatch_13(); 2054 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2055 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2056 } 2057 2058 static void 2059 client_init_dispatch(void) 2060 { 2061 if (compat20) 2062 client_init_dispatch_20(); 2063 else if (compat13) 2064 client_init_dispatch_13(); 2065 else 2066 client_init_dispatch_15(); 2067 } 2068 2069 /* client specific fatal cleanup */ 2070 void 2071 cleanup_exit(int i) 2072 { 2073 leave_raw_mode(); 2074 leave_non_blocking(); 2075 if (options.control_path != NULL && muxserver_sock != -1) 2076 unlink(options.control_path); 2077 _exit(i); 2078 } 2079