1 /* $OpenBSD: clientloop.c,v 1.176 2006/10/11 12:38:03 markus 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 "xmalloc.h" 90 #include "ssh.h" 91 #include "ssh1.h" 92 #include "ssh2.h" 93 #include "packet.h" 94 #include "buffer.h" 95 #include "compat.h" 96 #include "channels.h" 97 #include "dispatch.h" 98 #include "key.h" 99 #include "cipher.h" 100 #include "kex.h" 101 #include "log.h" 102 #include "readconf.h" 103 #include "clientloop.h" 104 #include "sshconnect.h" 105 #include "authfd.h" 106 #include "atomicio.h" 107 #include "sshpty.h" 108 #include "misc.h" 109 #include "monitor_fdpass.h" 110 #include "match.h" 111 #include "msg.h" 112 113 /* import options */ 114 extern Options options; 115 116 /* Flag indicating that stdin should be redirected from /dev/null. */ 117 extern int stdin_null_flag; 118 119 /* Flag indicating that no shell has been requested */ 120 extern int no_shell_flag; 121 122 /* Control socket */ 123 extern int control_fd; 124 125 /* 126 * Name of the host we are connecting to. This is the name given on the 127 * command line, or the HostName specified for the user-supplied name in a 128 * configuration file. 129 */ 130 extern char *host; 131 132 /* 133 * Flag to indicate that we have received a window change signal which has 134 * not yet been processed. This will cause a message indicating the new 135 * window size to be sent to the server a little later. This is volatile 136 * because this is updated in a signal handler. 137 */ 138 static volatile sig_atomic_t received_window_change_signal = 0; 139 static volatile sig_atomic_t received_signal = 0; 140 141 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 142 static int in_non_blocking_mode = 0; 143 144 /* Common data for the client loop code. */ 145 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 146 static int escape_char; /* Escape character. */ 147 static int escape_pending; /* Last character was the escape character */ 148 static int last_was_cr; /* Last character was a newline. */ 149 static int exit_status; /* Used to store the exit status of the command. */ 150 static int stdin_eof; /* EOF has been encountered on standard error. */ 151 static Buffer stdin_buffer; /* Buffer for stdin data. */ 152 static Buffer stdout_buffer; /* Buffer for stdout data. */ 153 static Buffer stderr_buffer; /* Buffer for stderr data. */ 154 static u_long stdin_bytes, stdout_bytes, stderr_bytes; 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 static int server_alive_timeouts = 0; 161 162 static void client_init_dispatch(void); 163 int session_ident = -1; 164 165 struct confirm_ctx { 166 int want_tty; 167 int want_subsys; 168 int want_x_fwd; 169 int want_agent_fwd; 170 Buffer cmd; 171 char *term; 172 struct termios tio; 173 char **env; 174 }; 175 176 /*XXX*/ 177 extern Kex *xxx_kex; 178 179 void ssh_process_session2_setup(int, int, int, Buffer *); 180 181 /* Restores stdin to blocking mode. */ 182 183 static void 184 leave_non_blocking(void) 185 { 186 if (in_non_blocking_mode) { 187 unset_nonblock(fileno(stdin)); 188 in_non_blocking_mode = 0; 189 } 190 } 191 192 /* Puts stdin terminal in non-blocking mode. */ 193 194 static void 195 enter_non_blocking(void) 196 { 197 in_non_blocking_mode = 1; 198 set_nonblock(fileno(stdin)); 199 } 200 201 /* 202 * Signal handler for the window change signal (SIGWINCH). This just sets a 203 * flag indicating that the window has changed. 204 */ 205 /*ARGSUSED */ 206 static void 207 window_change_handler(int sig) 208 { 209 received_window_change_signal = 1; 210 signal(SIGWINCH, window_change_handler); 211 } 212 213 /* 214 * Signal handler for signals that cause the program to terminate. These 215 * signals must be trapped to restore terminal modes. 216 */ 217 /*ARGSUSED */ 218 static void 219 signal_handler(int sig) 220 { 221 received_signal = sig; 222 quit_pending = 1; 223 } 224 225 /* 226 * Returns current time in seconds from Jan 1, 1970 with the maximum 227 * available resolution. 228 */ 229 230 static double 231 get_current_time(void) 232 { 233 struct timeval tv; 234 gettimeofday(&tv, NULL); 235 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 236 } 237 238 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 239 void 240 client_x11_get_proto(const char *display, const char *xauth_path, 241 u_int trusted, char **_proto, char **_data) 242 { 243 char cmd[1024]; 244 char line[512]; 245 char xdisplay[512]; 246 static char proto[512], data[512]; 247 FILE *f; 248 int got_data = 0, generated = 0, do_unlink = 0, i; 249 char *xauthdir, *xauthfile; 250 struct stat st; 251 252 xauthdir = xauthfile = NULL; 253 *_proto = proto; 254 *_data = data; 255 proto[0] = data[0] = '\0'; 256 257 if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) { 258 debug("No xauth program."); 259 } else { 260 if (display == NULL) { 261 debug("x11_get_proto: DISPLAY not set"); 262 return; 263 } 264 /* 265 * Handle FamilyLocal case where $DISPLAY does 266 * not match an authorization entry. For this we 267 * just try "xauth list unix:displaynum.screennum". 268 * XXX: "localhost" match to determine FamilyLocal 269 * is not perfect. 270 */ 271 if (strncmp(display, "localhost:", 10) == 0) { 272 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 273 display + 10); 274 display = xdisplay; 275 } 276 if (trusted == 0) { 277 xauthdir = xmalloc(MAXPATHLEN); 278 xauthfile = xmalloc(MAXPATHLEN); 279 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 280 if (mkdtemp(xauthdir) != NULL) { 281 do_unlink = 1; 282 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 283 xauthdir); 284 snprintf(cmd, sizeof(cmd), 285 "%s -f %s generate %s " SSH_X11_PROTO 286 " untrusted timeout 1200 2>" _PATH_DEVNULL, 287 xauth_path, xauthfile, display); 288 debug2("x11_get_proto: %s", cmd); 289 if (system(cmd) == 0) 290 generated = 1; 291 } 292 } 293 snprintf(cmd, sizeof(cmd), 294 "%s %s%s list %s 2>" _PATH_DEVNULL, 295 xauth_path, 296 generated ? "-f " : "" , 297 generated ? xauthfile : "", 298 display); 299 debug2("x11_get_proto: %s", cmd); 300 f = popen(cmd, "r"); 301 if (f && fgets(line, sizeof(line), f) && 302 sscanf(line, "%*s %511s %511s", proto, data) == 2) 303 got_data = 1; 304 if (f) 305 pclose(f); 306 } 307 308 if (do_unlink) { 309 unlink(xauthfile); 310 rmdir(xauthdir); 311 } 312 if (xauthdir) 313 xfree(xauthdir); 314 if (xauthfile) 315 xfree(xauthfile); 316 317 /* 318 * If we didn't get authentication data, just make up some 319 * data. The forwarding code will check the validity of the 320 * response anyway, and substitute this data. The X11 321 * server, however, will ignore this fake data and use 322 * whatever authentication mechanisms it was using otherwise 323 * for the local connection. 324 */ 325 if (!got_data) { 326 u_int32_t rnd = 0; 327 328 logit("Warning: No xauth data; " 329 "using fake authentication data for X11 forwarding."); 330 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 331 for (i = 0; i < 16; i++) { 332 if (i % 4 == 0) 333 rnd = arc4random(); 334 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 335 rnd & 0xff); 336 rnd >>= 8; 337 } 338 } 339 } 340 341 /* 342 * This is called when the interactive is entered. This checks if there is 343 * an EOF coming on stdin. We must check this explicitly, as select() does 344 * not appear to wake up when redirecting from /dev/null. 345 */ 346 347 static void 348 client_check_initial_eof_on_stdin(void) 349 { 350 int len; 351 char buf[1]; 352 353 /* 354 * If standard input is to be "redirected from /dev/null", we simply 355 * mark that we have seen an EOF and send an EOF message to the 356 * server. Otherwise, we try to read a single character; it appears 357 * that for some files, such /dev/null, select() never wakes up for 358 * read for this descriptor, which means that we never get EOF. This 359 * way we will get the EOF if stdin comes from /dev/null or similar. 360 */ 361 if (stdin_null_flag) { 362 /* Fake EOF on stdin. */ 363 debug("Sending eof."); 364 stdin_eof = 1; 365 packet_start(SSH_CMSG_EOF); 366 packet_send(); 367 } else { 368 enter_non_blocking(); 369 370 /* Check for immediate EOF on stdin. */ 371 len = read(fileno(stdin), buf, 1); 372 if (len == 0) { 373 /* EOF. Record that we have seen it and send EOF to server. */ 374 debug("Sending eof."); 375 stdin_eof = 1; 376 packet_start(SSH_CMSG_EOF); 377 packet_send(); 378 } else if (len > 0) { 379 /* 380 * Got data. We must store the data in the buffer, 381 * and also process it as an escape character if 382 * appropriate. 383 */ 384 if ((u_char) buf[0] == escape_char) 385 escape_pending = 1; 386 else 387 buffer_append(&stdin_buffer, buf, 1); 388 } 389 leave_non_blocking(); 390 } 391 } 392 393 394 /* 395 * Make packets from buffered stdin data, and buffer them for sending to the 396 * connection. 397 */ 398 399 static void 400 client_make_packets_from_stdin_data(void) 401 { 402 u_int len; 403 404 /* Send buffered stdin data to the server. */ 405 while (buffer_len(&stdin_buffer) > 0 && 406 packet_not_very_much_data_to_write()) { 407 len = buffer_len(&stdin_buffer); 408 /* Keep the packets at reasonable size. */ 409 if (len > packet_get_maxsize()) 410 len = packet_get_maxsize(); 411 packet_start(SSH_CMSG_STDIN_DATA); 412 packet_put_string(buffer_ptr(&stdin_buffer), len); 413 packet_send(); 414 buffer_consume(&stdin_buffer, len); 415 stdin_bytes += len; 416 /* If we have a pending EOF, send it now. */ 417 if (stdin_eof && buffer_len(&stdin_buffer) == 0) { 418 packet_start(SSH_CMSG_EOF); 419 packet_send(); 420 } 421 } 422 } 423 424 /* 425 * Checks if the client window has changed, and sends a packet about it to 426 * the server if so. The actual change is detected elsewhere (by a software 427 * interrupt on Unix); this just checks the flag and sends a message if 428 * appropriate. 429 */ 430 431 static void 432 client_check_window_change(void) 433 { 434 struct winsize ws; 435 436 if (! received_window_change_signal) 437 return; 438 /** XXX race */ 439 received_window_change_signal = 0; 440 441 debug2("client_check_window_change: changed"); 442 443 if (compat20) { 444 channel_send_window_changes(); 445 } else { 446 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 447 return; 448 packet_start(SSH_CMSG_WINDOW_SIZE); 449 packet_put_int((u_int)ws.ws_row); 450 packet_put_int((u_int)ws.ws_col); 451 packet_put_int((u_int)ws.ws_xpixel); 452 packet_put_int((u_int)ws.ws_ypixel); 453 packet_send(); 454 } 455 } 456 457 static void 458 client_global_request_reply(int type, u_int32_t seq, void *ctxt) 459 { 460 server_alive_timeouts = 0; 461 client_global_request_reply_fwd(type, seq, ctxt); 462 } 463 464 static void 465 server_alive_check(void) 466 { 467 if (++server_alive_timeouts > options.server_alive_count_max) { 468 logit("Timeout, server not responding."); 469 cleanup_exit(255); 470 } 471 packet_start(SSH2_MSG_GLOBAL_REQUEST); 472 packet_put_cstring("keepalive@openssh.com"); 473 packet_put_char(1); /* boolean: want reply */ 474 packet_send(); 475 } 476 477 /* 478 * Waits until the client can do something (some data becomes available on 479 * one of the file descriptors). 480 */ 481 static void 482 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 483 int *maxfdp, u_int *nallocp, int rekeying) 484 { 485 struct timeval tv, *tvp; 486 int ret; 487 488 /* Add any selections by the channel mechanism. */ 489 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); 490 491 if (!compat20) { 492 /* Read from the connection, unless our buffers are full. */ 493 if (buffer_len(&stdout_buffer) < buffer_high && 494 buffer_len(&stderr_buffer) < buffer_high && 495 channel_not_very_much_buffered_data()) 496 FD_SET(connection_in, *readsetp); 497 /* 498 * Read from stdin, unless we have seen EOF or have very much 499 * buffered data to send to the server. 500 */ 501 if (!stdin_eof && packet_not_very_much_data_to_write()) 502 FD_SET(fileno(stdin), *readsetp); 503 504 /* Select stdout/stderr if have data in buffer. */ 505 if (buffer_len(&stdout_buffer) > 0) 506 FD_SET(fileno(stdout), *writesetp); 507 if (buffer_len(&stderr_buffer) > 0) 508 FD_SET(fileno(stderr), *writesetp); 509 } else { 510 /* channel_prepare_select could have closed the last channel */ 511 if (session_closed && !channel_still_open() && 512 !packet_have_data_to_write()) { 513 /* clear mask since we did not call select() */ 514 memset(*readsetp, 0, *nallocp); 515 memset(*writesetp, 0, *nallocp); 516 return; 517 } else { 518 FD_SET(connection_in, *readsetp); 519 } 520 } 521 522 /* Select server connection if have data to write to the server. */ 523 if (packet_have_data_to_write()) 524 FD_SET(connection_out, *writesetp); 525 526 if (control_fd != -1) 527 FD_SET(control_fd, *readsetp); 528 529 /* 530 * Wait for something to happen. This will suspend the process until 531 * some selected descriptor can be read, written, or has some other 532 * event pending. 533 */ 534 535 if (options.server_alive_interval == 0 || !compat20) 536 tvp = NULL; 537 else { 538 tv.tv_sec = options.server_alive_interval; 539 tv.tv_usec = 0; 540 tvp = &tv; 541 } 542 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 543 if (ret < 0) { 544 char buf[100]; 545 546 /* 547 * We have to clear the select masks, because we return. 548 * We have to return, because the mainloop checks for the flags 549 * set by the signal handlers. 550 */ 551 memset(*readsetp, 0, *nallocp); 552 memset(*writesetp, 0, *nallocp); 553 554 if (errno == EINTR) 555 return; 556 /* Note: we might still have data in the buffers. */ 557 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 558 buffer_append(&stderr_buffer, buf, strlen(buf)); 559 quit_pending = 1; 560 } else if (ret == 0) 561 server_alive_check(); 562 } 563 564 static void 565 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 566 { 567 /* Flush stdout and stderr buffers. */ 568 if (buffer_len(bout) > 0) 569 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout)); 570 if (buffer_len(berr) > 0) 571 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr)); 572 573 leave_raw_mode(); 574 575 /* 576 * Free (and clear) the buffer to reduce the amount of data that gets 577 * written to swap. 578 */ 579 buffer_free(bin); 580 buffer_free(bout); 581 buffer_free(berr); 582 583 /* Send the suspend signal to the program itself. */ 584 kill(getpid(), SIGTSTP); 585 586 /* Reset window sizes in case they have changed */ 587 received_window_change_signal = 1; 588 589 /* OK, we have been continued by the user. Reinitialize buffers. */ 590 buffer_init(bin); 591 buffer_init(bout); 592 buffer_init(berr); 593 594 enter_raw_mode(); 595 } 596 597 static void 598 client_process_net_input(fd_set *readset) 599 { 600 int len; 601 char buf[8192]; 602 603 /* 604 * Read input from the server, and add any such data to the buffer of 605 * the packet subsystem. 606 */ 607 if (FD_ISSET(connection_in, readset)) { 608 /* Read as much as possible. */ 609 len = read(connection_in, buf, sizeof(buf)); 610 if (len == 0) { 611 /* Received EOF. The remote host has closed the connection. */ 612 snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", 613 host); 614 buffer_append(&stderr_buffer, buf, strlen(buf)); 615 quit_pending = 1; 616 return; 617 } 618 /* 619 * There is a kernel bug on Solaris that causes select to 620 * sometimes wake up even though there is no data available. 621 */ 622 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 623 len = 0; 624 625 if (len < 0) { 626 /* An error has encountered. Perhaps there is a network problem. */ 627 snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", 628 host, strerror(errno)); 629 buffer_append(&stderr_buffer, buf, strlen(buf)); 630 quit_pending = 1; 631 return; 632 } 633 packet_process_incoming(buf, len); 634 } 635 } 636 637 static void 638 client_subsystem_reply(int type, u_int32_t seq, void *ctxt) 639 { 640 int id; 641 Channel *c; 642 643 id = packet_get_int(); 644 packet_check_eom(); 645 646 if ((c = channel_lookup(id)) == NULL) { 647 error("%s: no channel for id %d", __func__, id); 648 return; 649 } 650 651 if (type == SSH2_MSG_CHANNEL_SUCCESS) 652 debug2("Request suceeded on channel %d", id); 653 else if (type == SSH2_MSG_CHANNEL_FAILURE) { 654 error("Request failed on channel %d", id); 655 channel_free(c); 656 } 657 } 658 659 static void 660 client_extra_session2_setup(int id, void *arg) 661 { 662 struct confirm_ctx *cctx = arg; 663 const char *display; 664 Channel *c; 665 int i; 666 667 if (cctx == NULL) 668 fatal("%s: cctx == NULL", __func__); 669 if ((c = channel_lookup(id)) == NULL) 670 fatal("%s: no channel for id %d", __func__, id); 671 672 display = getenv("DISPLAY"); 673 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) { 674 char *proto, *data; 675 /* Get reasonable local authentication information. */ 676 client_x11_get_proto(display, options.xauth_location, 677 options.forward_x11_trusted, &proto, &data); 678 /* Request forwarding with authentication spoofing. */ 679 debug("Requesting X11 forwarding with authentication spoofing."); 680 x11_request_forwarding_with_spoofing(id, display, proto, data); 681 /* XXX wait for reply */ 682 } 683 684 if (cctx->want_agent_fwd && options.forward_agent) { 685 debug("Requesting authentication agent forwarding."); 686 channel_request_start(id, "auth-agent-req@openssh.com", 0); 687 packet_send(); 688 } 689 690 client_session2_setup(id, cctx->want_tty, cctx->want_subsys, 691 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env, 692 client_subsystem_reply); 693 694 c->confirm_ctx = NULL; 695 buffer_free(&cctx->cmd); 696 xfree(cctx->term); 697 if (cctx->env != NULL) { 698 for (i = 0; cctx->env[i] != NULL; i++) 699 xfree(cctx->env[i]); 700 xfree(cctx->env); 701 } 702 xfree(cctx); 703 } 704 705 static void 706 client_process_control(fd_set *readset) 707 { 708 Buffer m; 709 Channel *c; 710 int client_fd, new_fd[3], ver, allowed; 711 socklen_t addrlen; 712 struct sockaddr_storage addr; 713 struct confirm_ctx *cctx; 714 char *cmd; 715 u_int i, len, env_len, command, flags; 716 uid_t euid; 717 gid_t egid; 718 719 /* 720 * Accept connection on control socket 721 */ 722 if (control_fd == -1 || !FD_ISSET(control_fd, readset)) 723 return; 724 725 memset(&addr, 0, sizeof(addr)); 726 addrlen = sizeof(addr); 727 if ((client_fd = accept(control_fd, 728 (struct sockaddr*)&addr, &addrlen)) == -1) { 729 error("%s accept: %s", __func__, strerror(errno)); 730 return; 731 } 732 733 if (getpeereid(client_fd, &euid, &egid) < 0) { 734 error("%s getpeereid failed: %s", __func__, strerror(errno)); 735 close(client_fd); 736 return; 737 } 738 if ((euid != 0) && (getuid() != euid)) { 739 error("control mode uid mismatch: peer euid %u != uid %u", 740 (u_int) euid, (u_int) getuid()); 741 close(client_fd); 742 return; 743 } 744 745 unset_nonblock(client_fd); 746 747 /* Read command */ 748 buffer_init(&m); 749 if (ssh_msg_recv(client_fd, &m) == -1) { 750 error("%s: client msg_recv failed", __func__); 751 close(client_fd); 752 buffer_free(&m); 753 return; 754 } 755 if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { 756 error("%s: wrong client version %d", __func__, ver); 757 buffer_free(&m); 758 close(client_fd); 759 return; 760 } 761 762 allowed = 1; 763 command = buffer_get_int(&m); 764 flags = buffer_get_int(&m); 765 766 buffer_clear(&m); 767 768 switch (command) { 769 case SSHMUX_COMMAND_OPEN: 770 if (options.control_master == SSHCTL_MASTER_ASK || 771 options.control_master == SSHCTL_MASTER_AUTO_ASK) 772 allowed = ask_permission("Allow shared connection " 773 "to %s? ", host); 774 /* continue below */ 775 break; 776 case SSHMUX_COMMAND_TERMINATE: 777 if (options.control_master == SSHCTL_MASTER_ASK || 778 options.control_master == SSHCTL_MASTER_AUTO_ASK) 779 allowed = ask_permission("Terminate shared connection " 780 "to %s? ", host); 781 if (allowed) 782 quit_pending = 1; 783 /* FALLTHROUGH */ 784 case SSHMUX_COMMAND_ALIVE_CHECK: 785 /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */ 786 buffer_clear(&m); 787 buffer_put_int(&m, allowed); 788 buffer_put_int(&m, getpid()); 789 if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { 790 error("%s: client msg_send failed", __func__); 791 close(client_fd); 792 buffer_free(&m); 793 return; 794 } 795 buffer_free(&m); 796 close(client_fd); 797 return; 798 default: 799 error("Unsupported command %d", command); 800 buffer_free(&m); 801 close(client_fd); 802 return; 803 } 804 805 /* Reply for SSHMUX_COMMAND_OPEN */ 806 buffer_clear(&m); 807 buffer_put_int(&m, allowed); 808 buffer_put_int(&m, getpid()); 809 if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { 810 error("%s: client msg_send failed", __func__); 811 close(client_fd); 812 buffer_free(&m); 813 return; 814 } 815 816 if (!allowed) { 817 error("Refused control connection"); 818 close(client_fd); 819 buffer_free(&m); 820 return; 821 } 822 823 buffer_clear(&m); 824 if (ssh_msg_recv(client_fd, &m) == -1) { 825 error("%s: client msg_recv failed", __func__); 826 close(client_fd); 827 buffer_free(&m); 828 return; 829 } 830 if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { 831 error("%s: wrong client version %d", __func__, ver); 832 buffer_free(&m); 833 close(client_fd); 834 return; 835 } 836 837 cctx = xcalloc(1, sizeof(*cctx)); 838 cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0; 839 cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0; 840 cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0; 841 cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0; 842 cctx->term = buffer_get_string(&m, &len); 843 844 cmd = buffer_get_string(&m, &len); 845 buffer_init(&cctx->cmd); 846 buffer_append(&cctx->cmd, cmd, strlen(cmd)); 847 848 env_len = buffer_get_int(&m); 849 env_len = MIN(env_len, 4096); 850 debug3("%s: receiving %d env vars", __func__, env_len); 851 if (env_len != 0) { 852 cctx->env = xcalloc(env_len + 1, sizeof(*cctx->env)); 853 for (i = 0; i < env_len; i++) 854 cctx->env[i] = buffer_get_string(&m, &len); 855 cctx->env[i] = NULL; 856 } 857 858 debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__, 859 cctx->want_tty, cctx->want_subsys, cmd); 860 xfree(cmd); 861 862 /* Gather fds from client */ 863 new_fd[0] = mm_receive_fd(client_fd); 864 new_fd[1] = mm_receive_fd(client_fd); 865 new_fd[2] = mm_receive_fd(client_fd); 866 867 debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__, 868 new_fd[0], new_fd[1], new_fd[2]); 869 870 /* Try to pick up ttymodes from client before it goes raw */ 871 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1) 872 error("%s: tcgetattr: %s", __func__, strerror(errno)); 873 874 /* This roundtrip is just for synchronisation of ttymodes */ 875 buffer_clear(&m); 876 if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { 877 error("%s: client msg_send failed", __func__); 878 close(client_fd); 879 close(new_fd[0]); 880 close(new_fd[1]); 881 close(new_fd[2]); 882 buffer_free(&m); 883 xfree(cctx->term); 884 if (env_len != 0) { 885 for (i = 0; i < env_len; i++) 886 xfree(cctx->env[i]); 887 xfree(cctx->env); 888 } 889 return; 890 } 891 buffer_free(&m); 892 893 /* enable nonblocking unless tty */ 894 if (!isatty(new_fd[0])) 895 set_nonblock(new_fd[0]); 896 if (!isatty(new_fd[1])) 897 set_nonblock(new_fd[1]); 898 if (!isatty(new_fd[2])) 899 set_nonblock(new_fd[2]); 900 901 set_nonblock(client_fd); 902 903 c = channel_new("session", SSH_CHANNEL_OPENING, 904 new_fd[0], new_fd[1], new_fd[2], 905 CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT, 906 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 907 908 /* XXX */ 909 c->ctl_fd = client_fd; 910 911 debug3("%s: channel_new: %d", __func__, c->self); 912 913 channel_send_open(c->self); 914 channel_register_confirm(c->self, client_extra_session2_setup, cctx); 915 } 916 917 static void 918 process_cmdline(void) 919 { 920 void (*handler)(int); 921 char *s, *cmd, *cancel_host; 922 int delete = 0; 923 int local = 0; 924 u_short cancel_port; 925 Forward fwd; 926 927 leave_raw_mode(); 928 handler = signal(SIGINT, SIG_IGN); 929 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 930 if (s == NULL) 931 goto out; 932 while (*s && isspace(*s)) 933 s++; 934 if (*s == '-') 935 s++; /* Skip cmdline '-', if any */ 936 if (*s == '\0') 937 goto out; 938 939 if (*s == 'h' || *s == 'H' || *s == '?') { 940 logit("Commands:"); 941 logit(" -L[bind_address:]port:host:hostport " 942 "Request local forward"); 943 logit(" -R[bind_address:]port:host:hostport " 944 "Request remote forward"); 945 logit(" -KR[bind_address:]port " 946 "Cancel remote forward"); 947 if (!options.permit_local_command) 948 goto out; 949 logit(" !args " 950 "Execute local command"); 951 goto out; 952 } 953 954 if (*s == '!' && options.permit_local_command) { 955 s++; 956 ssh_local_cmd(s); 957 goto out; 958 } 959 960 if (*s == 'K') { 961 delete = 1; 962 s++; 963 } 964 if (*s != 'L' && *s != 'R') { 965 logit("Invalid command."); 966 goto out; 967 } 968 if (*s == 'L') 969 local = 1; 970 if (local && delete) { 971 logit("Not supported."); 972 goto out; 973 } 974 if ((!local || delete) && !compat20) { 975 logit("Not supported for SSH protocol version 1."); 976 goto out; 977 } 978 979 s++; 980 while (*s && isspace(*s)) 981 s++; 982 983 if (delete) { 984 cancel_port = 0; 985 cancel_host = hpdelim(&s); /* may be NULL */ 986 if (s != NULL) { 987 cancel_port = a2port(s); 988 cancel_host = cleanhostname(cancel_host); 989 } else { 990 cancel_port = a2port(cancel_host); 991 cancel_host = NULL; 992 } 993 if (cancel_port == 0) { 994 logit("Bad forwarding close port"); 995 goto out; 996 } 997 channel_request_rforward_cancel(cancel_host, cancel_port); 998 } else { 999 if (!parse_forward(&fwd, s)) { 1000 logit("Bad forwarding specification."); 1001 goto out; 1002 } 1003 if (local) { 1004 if (channel_setup_local_fwd_listener(fwd.listen_host, 1005 fwd.listen_port, fwd.connect_host, 1006 fwd.connect_port, options.gateway_ports) < 0) { 1007 logit("Port forwarding failed."); 1008 goto out; 1009 } 1010 } else { 1011 if (channel_request_remote_forwarding(fwd.listen_host, 1012 fwd.listen_port, fwd.connect_host, 1013 fwd.connect_port) < 0) { 1014 logit("Port forwarding failed."); 1015 goto out; 1016 } 1017 } 1018 1019 logit("Forwarding port."); 1020 } 1021 1022 out: 1023 signal(SIGINT, handler); 1024 enter_raw_mode(); 1025 if (cmd) 1026 xfree(cmd); 1027 } 1028 1029 /* process the characters one by one */ 1030 static int 1031 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) 1032 { 1033 char string[1024]; 1034 pid_t pid; 1035 int bytes = 0; 1036 u_int i; 1037 u_char ch; 1038 char *s; 1039 1040 if (len <= 0) 1041 return (0); 1042 1043 for (i = 0; i < (u_int)len; i++) { 1044 /* Get one character at a time. */ 1045 ch = buf[i]; 1046 1047 if (escape_pending) { 1048 /* We have previously seen an escape character. */ 1049 /* Clear the flag now. */ 1050 escape_pending = 0; 1051 1052 /* Process the escaped character. */ 1053 switch (ch) { 1054 case '.': 1055 /* Terminate the connection. */ 1056 snprintf(string, sizeof string, "%c.\r\n", escape_char); 1057 buffer_append(berr, string, strlen(string)); 1058 1059 quit_pending = 1; 1060 return -1; 1061 1062 case 'Z' - 64: 1063 /* Suspend the program. */ 1064 /* Print a message to that effect to the user. */ 1065 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); 1066 buffer_append(berr, string, strlen(string)); 1067 1068 /* Restore terminal modes and suspend. */ 1069 client_suspend_self(bin, bout, berr); 1070 1071 /* We have been continued. */ 1072 continue; 1073 1074 case 'B': 1075 if (compat20) { 1076 snprintf(string, sizeof string, 1077 "%cB\r\n", escape_char); 1078 buffer_append(berr, string, 1079 strlen(string)); 1080 channel_request_start(session_ident, 1081 "break", 0); 1082 packet_put_int(1000); 1083 packet_send(); 1084 } 1085 continue; 1086 1087 case 'R': 1088 if (compat20) { 1089 if (datafellows & SSH_BUG_NOREKEY) 1090 logit("Server does not support re-keying"); 1091 else 1092 need_rekeying = 1; 1093 } 1094 continue; 1095 1096 case '&': 1097 /* 1098 * Detach the program (continue to serve connections, 1099 * but put in background and no more new connections). 1100 */ 1101 /* Restore tty modes. */ 1102 leave_raw_mode(); 1103 1104 /* Stop listening for new connections. */ 1105 channel_stop_listening(); 1106 1107 snprintf(string, sizeof string, 1108 "%c& [backgrounded]\n", escape_char); 1109 buffer_append(berr, string, strlen(string)); 1110 1111 /* Fork into background. */ 1112 pid = fork(); 1113 if (pid < 0) { 1114 error("fork: %.100s", strerror(errno)); 1115 continue; 1116 } 1117 if (pid != 0) { /* This is the parent. */ 1118 /* The parent just exits. */ 1119 exit(0); 1120 } 1121 /* The child continues serving connections. */ 1122 if (compat20) { 1123 buffer_append(bin, "\004", 1); 1124 /* fake EOF on stdin */ 1125 return -1; 1126 } else if (!stdin_eof) { 1127 /* 1128 * Sending SSH_CMSG_EOF alone does not always appear 1129 * to be enough. So we try to send an EOF character 1130 * first. 1131 */ 1132 packet_start(SSH_CMSG_STDIN_DATA); 1133 packet_put_string("\004", 1); 1134 packet_send(); 1135 /* Close stdin. */ 1136 stdin_eof = 1; 1137 if (buffer_len(bin) == 0) { 1138 packet_start(SSH_CMSG_EOF); 1139 packet_send(); 1140 } 1141 } 1142 continue; 1143 1144 case '?': 1145 snprintf(string, sizeof string, 1146 "%c?\r\n\ 1147 Supported escape sequences:\r\n\ 1148 %c. - terminate connection\r\n\ 1149 %cB - send a BREAK to the remote system\r\n\ 1150 %cC - open a command line\r\n\ 1151 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1152 %c^Z - suspend ssh\r\n\ 1153 %c# - list forwarded connections\r\n\ 1154 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1155 %c? - this message\r\n\ 1156 %c%c - send the escape character by typing it twice\r\n\ 1157 (Note that escapes are only recognized immediately after newline.)\r\n", 1158 escape_char, escape_char, escape_char, escape_char, 1159 escape_char, escape_char, escape_char, escape_char, 1160 escape_char, escape_char, escape_char); 1161 buffer_append(berr, string, strlen(string)); 1162 continue; 1163 1164 case '#': 1165 snprintf(string, sizeof string, "%c#\r\n", escape_char); 1166 buffer_append(berr, string, strlen(string)); 1167 s = channel_open_message(); 1168 buffer_append(berr, s, strlen(s)); 1169 xfree(s); 1170 continue; 1171 1172 case 'C': 1173 process_cmdline(); 1174 continue; 1175 1176 default: 1177 if (ch != escape_char) { 1178 buffer_put_char(bin, escape_char); 1179 bytes++; 1180 } 1181 /* Escaped characters fall through here */ 1182 break; 1183 } 1184 } else { 1185 /* 1186 * The previous character was not an escape char. Check if this 1187 * is an escape. 1188 */ 1189 if (last_was_cr && ch == escape_char) { 1190 /* It is. Set the flag and continue to next character. */ 1191 escape_pending = 1; 1192 continue; 1193 } 1194 } 1195 1196 /* 1197 * Normal character. Record whether it was a newline, 1198 * and append it to the buffer. 1199 */ 1200 last_was_cr = (ch == '\r' || ch == '\n'); 1201 buffer_put_char(bin, ch); 1202 bytes++; 1203 } 1204 return bytes; 1205 } 1206 1207 static void 1208 client_process_input(fd_set *readset) 1209 { 1210 int len; 1211 char buf[8192]; 1212 1213 /* Read input from stdin. */ 1214 if (FD_ISSET(fileno(stdin), readset)) { 1215 /* Read as much as possible. */ 1216 len = read(fileno(stdin), buf, sizeof(buf)); 1217 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 1218 return; /* we'll try again later */ 1219 if (len <= 0) { 1220 /* 1221 * Received EOF or error. They are treated 1222 * similarly, except that an error message is printed 1223 * if it was an error condition. 1224 */ 1225 if (len < 0) { 1226 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); 1227 buffer_append(&stderr_buffer, buf, strlen(buf)); 1228 } 1229 /* Mark that we have seen EOF. */ 1230 stdin_eof = 1; 1231 /* 1232 * Send an EOF message to the server unless there is 1233 * data in the buffer. If there is data in the 1234 * buffer, no message will be sent now. Code 1235 * elsewhere will send the EOF when the buffer 1236 * becomes empty if stdin_eof is set. 1237 */ 1238 if (buffer_len(&stdin_buffer) == 0) { 1239 packet_start(SSH_CMSG_EOF); 1240 packet_send(); 1241 } 1242 } else if (escape_char == SSH_ESCAPECHAR_NONE) { 1243 /* 1244 * Normal successful read, and no escape character. 1245 * Just append the data to buffer. 1246 */ 1247 buffer_append(&stdin_buffer, buf, len); 1248 } else { 1249 /* 1250 * Normal, successful read. But we have an escape character 1251 * and have to process the characters one by one. 1252 */ 1253 if (process_escapes(&stdin_buffer, &stdout_buffer, 1254 &stderr_buffer, buf, len) == -1) 1255 return; 1256 } 1257 } 1258 } 1259 1260 static void 1261 client_process_output(fd_set *writeset) 1262 { 1263 int len; 1264 char buf[100]; 1265 1266 /* Write buffered output to stdout. */ 1267 if (FD_ISSET(fileno(stdout), writeset)) { 1268 /* Write as much data as possible. */ 1269 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1270 buffer_len(&stdout_buffer)); 1271 if (len <= 0) { 1272 if (errno == EINTR || errno == EAGAIN) 1273 len = 0; 1274 else { 1275 /* 1276 * An error or EOF was encountered. Put an 1277 * error message to stderr buffer. 1278 */ 1279 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); 1280 buffer_append(&stderr_buffer, buf, strlen(buf)); 1281 quit_pending = 1; 1282 return; 1283 } 1284 } 1285 /* Consume printed data from the buffer. */ 1286 buffer_consume(&stdout_buffer, len); 1287 stdout_bytes += len; 1288 } 1289 /* Write buffered output to stderr. */ 1290 if (FD_ISSET(fileno(stderr), writeset)) { 1291 /* Write as much data as possible. */ 1292 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1293 buffer_len(&stderr_buffer)); 1294 if (len <= 0) { 1295 if (errno == EINTR || errno == EAGAIN) 1296 len = 0; 1297 else { 1298 /* EOF or error, but can't even print error message. */ 1299 quit_pending = 1; 1300 return; 1301 } 1302 } 1303 /* Consume printed characters from the buffer. */ 1304 buffer_consume(&stderr_buffer, len); 1305 stderr_bytes += len; 1306 } 1307 } 1308 1309 /* 1310 * Get packets from the connection input buffer, and process them as long as 1311 * there are packets available. 1312 * 1313 * Any unknown packets received during the actual 1314 * session cause the session to terminate. This is 1315 * intended to make debugging easier since no 1316 * confirmations are sent. Any compatible protocol 1317 * extensions must be negotiated during the 1318 * preparatory phase. 1319 */ 1320 1321 static void 1322 client_process_buffered_input_packets(void) 1323 { 1324 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL); 1325 } 1326 1327 /* scan buf[] for '~' before sending data to the peer */ 1328 1329 static int 1330 simple_escape_filter(Channel *c, char *buf, int len) 1331 { 1332 /* XXX we assume c->extended is writeable */ 1333 return process_escapes(&c->input, &c->output, &c->extended, buf, len); 1334 } 1335 1336 static void 1337 client_channel_closed(int id, void *arg) 1338 { 1339 channel_cancel_cleanup(id); 1340 session_closed = 1; 1341 leave_raw_mode(); 1342 } 1343 1344 /* 1345 * Implements the interactive session with the server. This is called after 1346 * the user has been authenticated, and a command has been started on the 1347 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1348 * used as an escape character for terminating or suspending the session. 1349 */ 1350 1351 int 1352 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1353 { 1354 fd_set *readset = NULL, *writeset = NULL; 1355 double start_time, total_time; 1356 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1357 u_int nalloc = 0; 1358 char buf[100]; 1359 1360 debug("Entering interactive session."); 1361 1362 start_time = get_current_time(); 1363 1364 /* Initialize variables. */ 1365 escape_pending = 0; 1366 last_was_cr = 1; 1367 exit_status = -1; 1368 stdin_eof = 0; 1369 buffer_high = 64 * 1024; 1370 connection_in = packet_get_connection_in(); 1371 connection_out = packet_get_connection_out(); 1372 max_fd = MAX(connection_in, connection_out); 1373 if (control_fd != -1) 1374 max_fd = MAX(max_fd, control_fd); 1375 1376 if (!compat20) { 1377 /* enable nonblocking unless tty */ 1378 if (!isatty(fileno(stdin))) 1379 set_nonblock(fileno(stdin)); 1380 if (!isatty(fileno(stdout))) 1381 set_nonblock(fileno(stdout)); 1382 if (!isatty(fileno(stderr))) 1383 set_nonblock(fileno(stderr)); 1384 max_fd = MAX(max_fd, fileno(stdin)); 1385 max_fd = MAX(max_fd, fileno(stdout)); 1386 max_fd = MAX(max_fd, fileno(stderr)); 1387 } 1388 stdin_bytes = 0; 1389 stdout_bytes = 0; 1390 stderr_bytes = 0; 1391 quit_pending = 0; 1392 escape_char = escape_char_arg; 1393 1394 /* Initialize buffers. */ 1395 buffer_init(&stdin_buffer); 1396 buffer_init(&stdout_buffer); 1397 buffer_init(&stderr_buffer); 1398 1399 client_init_dispatch(); 1400 1401 /* 1402 * Set signal handlers, (e.g. to restore non-blocking mode) 1403 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1404 */ 1405 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1406 signal(SIGHUP, signal_handler); 1407 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1408 signal(SIGINT, signal_handler); 1409 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1410 signal(SIGQUIT, signal_handler); 1411 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1412 signal(SIGTERM, signal_handler); 1413 signal(SIGWINCH, window_change_handler); 1414 1415 if (have_pty) 1416 enter_raw_mode(); 1417 1418 if (compat20) { 1419 session_ident = ssh2_chan_id; 1420 if (escape_char != SSH_ESCAPECHAR_NONE) 1421 channel_register_filter(session_ident, 1422 simple_escape_filter, NULL); 1423 if (session_ident != -1) 1424 channel_register_cleanup(session_ident, 1425 client_channel_closed, 0); 1426 } else { 1427 /* Check if we should immediately send eof on stdin. */ 1428 client_check_initial_eof_on_stdin(); 1429 } 1430 1431 /* Main loop of the client for the interactive session mode. */ 1432 while (!quit_pending) { 1433 1434 /* Process buffered packets sent by the server. */ 1435 client_process_buffered_input_packets(); 1436 1437 if (compat20 && session_closed && !channel_still_open()) 1438 break; 1439 1440 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1441 1442 if (rekeying) { 1443 debug("rekeying in progress"); 1444 } else { 1445 /* 1446 * Make packets of buffered stdin data, and buffer 1447 * them for sending to the server. 1448 */ 1449 if (!compat20) 1450 client_make_packets_from_stdin_data(); 1451 1452 /* 1453 * Make packets from buffered channel data, and 1454 * enqueue them for sending to the server. 1455 */ 1456 if (packet_not_very_much_data_to_write()) 1457 channel_output_poll(); 1458 1459 /* 1460 * Check if the window size has changed, and buffer a 1461 * message about it to the server if so. 1462 */ 1463 client_check_window_change(); 1464 1465 if (quit_pending) 1466 break; 1467 } 1468 /* 1469 * Wait until we have something to do (something becomes 1470 * available on one of the descriptors). 1471 */ 1472 max_fd2 = max_fd; 1473 client_wait_until_can_do_something(&readset, &writeset, 1474 &max_fd2, &nalloc, rekeying); 1475 1476 if (quit_pending) 1477 break; 1478 1479 /* Do channel operations unless rekeying in progress. */ 1480 if (!rekeying) { 1481 channel_after_select(readset, writeset); 1482 if (need_rekeying || packet_need_rekeying()) { 1483 debug("need rekeying"); 1484 xxx_kex->done = 0; 1485 kex_send_kexinit(xxx_kex); 1486 need_rekeying = 0; 1487 } 1488 } 1489 1490 /* Buffer input from the connection. */ 1491 client_process_net_input(readset); 1492 1493 /* Accept control connections. */ 1494 client_process_control(readset); 1495 1496 if (quit_pending) 1497 break; 1498 1499 if (!compat20) { 1500 /* Buffer data from stdin */ 1501 client_process_input(readset); 1502 /* 1503 * Process output to stdout and stderr. Output to 1504 * the connection is processed elsewhere (above). 1505 */ 1506 client_process_output(writeset); 1507 } 1508 1509 /* Send as much buffered packet data as possible to the sender. */ 1510 if (FD_ISSET(connection_out, writeset)) 1511 packet_write_poll(); 1512 } 1513 if (readset) 1514 xfree(readset); 1515 if (writeset) 1516 xfree(writeset); 1517 1518 /* Terminate the session. */ 1519 1520 /* Stop watching for window change. */ 1521 signal(SIGWINCH, SIG_DFL); 1522 1523 channel_free_all(); 1524 1525 if (have_pty) 1526 leave_raw_mode(); 1527 1528 /* restore blocking io */ 1529 if (!isatty(fileno(stdin))) 1530 unset_nonblock(fileno(stdin)); 1531 if (!isatty(fileno(stdout))) 1532 unset_nonblock(fileno(stdout)); 1533 if (!isatty(fileno(stderr))) 1534 unset_nonblock(fileno(stderr)); 1535 1536 /* 1537 * If there was no shell or command requested, there will be no remote 1538 * exit status to be returned. In that case, clear error code if the 1539 * connection was deliberately terminated at this end. 1540 */ 1541 if (no_shell_flag && received_signal == SIGTERM) { 1542 received_signal = 0; 1543 exit_status = 0; 1544 } 1545 1546 if (received_signal) 1547 fatal("Killed by signal %d.", (int) received_signal); 1548 1549 /* 1550 * In interactive mode (with pseudo tty) display a message indicating 1551 * that the connection has been closed. 1552 */ 1553 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1554 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); 1555 buffer_append(&stderr_buffer, buf, strlen(buf)); 1556 } 1557 1558 /* Output any buffered data for stdout. */ 1559 while (buffer_len(&stdout_buffer) > 0) { 1560 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1561 buffer_len(&stdout_buffer)); 1562 if (len <= 0) { 1563 error("Write failed flushing stdout buffer."); 1564 break; 1565 } 1566 buffer_consume(&stdout_buffer, len); 1567 stdout_bytes += len; 1568 } 1569 1570 /* Output any buffered data for stderr. */ 1571 while (buffer_len(&stderr_buffer) > 0) { 1572 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1573 buffer_len(&stderr_buffer)); 1574 if (len <= 0) { 1575 error("Write failed flushing stderr buffer."); 1576 break; 1577 } 1578 buffer_consume(&stderr_buffer, len); 1579 stderr_bytes += len; 1580 } 1581 1582 /* Clear and free any buffers. */ 1583 memset(buf, 0, sizeof(buf)); 1584 buffer_free(&stdin_buffer); 1585 buffer_free(&stdout_buffer); 1586 buffer_free(&stderr_buffer); 1587 1588 /* Report bytes transferred, and transfer rates. */ 1589 total_time = get_current_time() - start_time; 1590 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", 1591 stdin_bytes, stdout_bytes, stderr_bytes, total_time); 1592 if (total_time > 0) 1593 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", 1594 stdin_bytes / total_time, stdout_bytes / total_time, 1595 stderr_bytes / total_time); 1596 1597 /* Return the exit status of the program. */ 1598 debug("Exit status %d", exit_status); 1599 return exit_status; 1600 } 1601 1602 /*********/ 1603 1604 static void 1605 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1606 { 1607 u_int data_len; 1608 char *data = packet_get_string(&data_len); 1609 packet_check_eom(); 1610 buffer_append(&stdout_buffer, data, data_len); 1611 memset(data, 0, data_len); 1612 xfree(data); 1613 } 1614 static void 1615 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1616 { 1617 u_int data_len; 1618 char *data = packet_get_string(&data_len); 1619 packet_check_eom(); 1620 buffer_append(&stderr_buffer, data, data_len); 1621 memset(data, 0, data_len); 1622 xfree(data); 1623 } 1624 static void 1625 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1626 { 1627 exit_status = packet_get_int(); 1628 packet_check_eom(); 1629 /* Acknowledge the exit. */ 1630 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1631 packet_send(); 1632 /* 1633 * Must wait for packet to be sent since we are 1634 * exiting the loop. 1635 */ 1636 packet_write_wait(); 1637 /* Flag that we want to exit. */ 1638 quit_pending = 1; 1639 } 1640 static void 1641 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1642 { 1643 Channel *c = NULL; 1644 int remote_id, sock; 1645 1646 /* Read the remote channel number from the message. */ 1647 remote_id = packet_get_int(); 1648 packet_check_eom(); 1649 1650 /* 1651 * Get a connection to the local authentication agent (this may again 1652 * get forwarded). 1653 */ 1654 sock = ssh_get_authentication_socket(); 1655 1656 /* 1657 * If we could not connect the agent, send an error message back to 1658 * the server. This should never happen unless the agent dies, 1659 * because authentication forwarding is only enabled if we have an 1660 * agent. 1661 */ 1662 if (sock >= 0) { 1663 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1664 -1, 0, 0, 0, "authentication agent connection", 1); 1665 c->remote_id = remote_id; 1666 c->force_drain = 1; 1667 } 1668 if (c == NULL) { 1669 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1670 packet_put_int(remote_id); 1671 } else { 1672 /* Send a confirmation to the remote host. */ 1673 debug("Forwarding authentication connection."); 1674 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1675 packet_put_int(remote_id); 1676 packet_put_int(c->self); 1677 } 1678 packet_send(); 1679 } 1680 1681 static Channel * 1682 client_request_forwarded_tcpip(const char *request_type, int rchan) 1683 { 1684 Channel *c = NULL; 1685 char *listen_address, *originator_address; 1686 int listen_port, originator_port; 1687 int sock; 1688 1689 /* Get rest of the packet */ 1690 listen_address = packet_get_string(NULL); 1691 listen_port = packet_get_int(); 1692 originator_address = packet_get_string(NULL); 1693 originator_port = packet_get_int(); 1694 packet_check_eom(); 1695 1696 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d", 1697 listen_address, listen_port, originator_address, originator_port); 1698 1699 sock = channel_connect_by_listen_address(listen_port); 1700 if (sock < 0) { 1701 xfree(originator_address); 1702 xfree(listen_address); 1703 return NULL; 1704 } 1705 c = channel_new("forwarded-tcpip", 1706 SSH_CHANNEL_CONNECTING, sock, sock, -1, 1707 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1708 originator_address, 1); 1709 xfree(originator_address); 1710 xfree(listen_address); 1711 return c; 1712 } 1713 1714 static Channel * 1715 client_request_x11(const char *request_type, int rchan) 1716 { 1717 Channel *c = NULL; 1718 char *originator; 1719 int originator_port; 1720 int sock; 1721 1722 if (!options.forward_x11) { 1723 error("Warning: ssh server tried X11 forwarding."); 1724 error("Warning: this is probably a break-in attempt by a malicious server."); 1725 return NULL; 1726 } 1727 originator = packet_get_string(NULL); 1728 if (datafellows & SSH_BUG_X11FWD) { 1729 debug2("buggy server: x11 request w/o originator_port"); 1730 originator_port = 0; 1731 } else { 1732 originator_port = packet_get_int(); 1733 } 1734 packet_check_eom(); 1735 /* XXX check permission */ 1736 debug("client_request_x11: request from %s %d", originator, 1737 originator_port); 1738 xfree(originator); 1739 sock = x11_connect_display(); 1740 if (sock < 0) 1741 return NULL; 1742 c = channel_new("x11", 1743 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1744 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1745 c->force_drain = 1; 1746 return c; 1747 } 1748 1749 static Channel * 1750 client_request_agent(const char *request_type, int rchan) 1751 { 1752 Channel *c = NULL; 1753 int sock; 1754 1755 if (!options.forward_agent) { 1756 error("Warning: ssh server tried agent forwarding."); 1757 error("Warning: this is probably a break-in attempt by a malicious server."); 1758 return NULL; 1759 } 1760 sock = ssh_get_authentication_socket(); 1761 if (sock < 0) 1762 return NULL; 1763 c = channel_new("authentication agent connection", 1764 SSH_CHANNEL_OPEN, sock, sock, -1, 1765 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1766 "authentication agent connection", 1); 1767 c->force_drain = 1; 1768 return c; 1769 } 1770 1771 /* XXXX move to generic input handler */ 1772 static void 1773 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1774 { 1775 Channel *c = NULL; 1776 char *ctype; 1777 int rchan; 1778 u_int rmaxpack, rwindow, len; 1779 1780 ctype = packet_get_string(&len); 1781 rchan = packet_get_int(); 1782 rwindow = packet_get_int(); 1783 rmaxpack = packet_get_int(); 1784 1785 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1786 ctype, rchan, rwindow, rmaxpack); 1787 1788 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1789 c = client_request_forwarded_tcpip(ctype, rchan); 1790 } else if (strcmp(ctype, "x11") == 0) { 1791 c = client_request_x11(ctype, rchan); 1792 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1793 c = client_request_agent(ctype, rchan); 1794 } 1795 /* XXX duplicate : */ 1796 if (c != NULL) { 1797 debug("confirm %s", ctype); 1798 c->remote_id = rchan; 1799 c->remote_window = rwindow; 1800 c->remote_maxpacket = rmaxpack; 1801 if (c->type != SSH_CHANNEL_CONNECTING) { 1802 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1803 packet_put_int(c->remote_id); 1804 packet_put_int(c->self); 1805 packet_put_int(c->local_window); 1806 packet_put_int(c->local_maxpacket); 1807 packet_send(); 1808 } 1809 } else { 1810 debug("failure %s", ctype); 1811 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1812 packet_put_int(rchan); 1813 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1814 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1815 packet_put_cstring("open failed"); 1816 packet_put_cstring(""); 1817 } 1818 packet_send(); 1819 } 1820 xfree(ctype); 1821 } 1822 static void 1823 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1824 { 1825 Channel *c = NULL; 1826 int exitval, id, reply, success = 0; 1827 char *rtype; 1828 1829 id = packet_get_int(); 1830 rtype = packet_get_string(NULL); 1831 reply = packet_get_char(); 1832 1833 debug("client_input_channel_req: channel %d rtype %s reply %d", 1834 id, rtype, reply); 1835 1836 if (id == -1) { 1837 error("client_input_channel_req: request for channel -1"); 1838 } else if ((c = channel_lookup(id)) == NULL) { 1839 error("client_input_channel_req: channel %d: unknown channel", id); 1840 } else if (strcmp(rtype, "exit-status") == 0) { 1841 exitval = packet_get_int(); 1842 if (id == session_ident) { 1843 success = 1; 1844 exit_status = exitval; 1845 } else if (c->ctl_fd == -1) { 1846 error("client_input_channel_req: unexpected channel %d", 1847 session_ident); 1848 } else { 1849 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1850 success = 1; 1851 } 1852 packet_check_eom(); 1853 } 1854 if (reply) { 1855 packet_start(success ? 1856 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1857 packet_put_int(id); 1858 packet_send(); 1859 } 1860 xfree(rtype); 1861 } 1862 static void 1863 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1864 { 1865 char *rtype; 1866 int want_reply; 1867 int success = 0; 1868 1869 rtype = packet_get_string(NULL); 1870 want_reply = packet_get_char(); 1871 debug("client_input_global_request: rtype %s want_reply %d", 1872 rtype, want_reply); 1873 if (want_reply) { 1874 packet_start(success ? 1875 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1876 packet_send(); 1877 packet_write_wait(); 1878 } 1879 xfree(rtype); 1880 } 1881 1882 void 1883 client_session2_setup(int id, int want_tty, int want_subsystem, 1884 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env, 1885 dispatch_fn *subsys_repl) 1886 { 1887 int len; 1888 Channel *c = NULL; 1889 1890 debug2("%s: id %d", __func__, id); 1891 1892 if ((c = channel_lookup(id)) == NULL) 1893 fatal("client_session2_setup: channel %d: unknown channel", id); 1894 1895 if (want_tty) { 1896 struct winsize ws; 1897 struct termios tio; 1898 1899 /* Store window size in the packet. */ 1900 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1901 memset(&ws, 0, sizeof(ws)); 1902 1903 channel_request_start(id, "pty-req", 0); 1904 packet_put_cstring(term != NULL ? term : ""); 1905 packet_put_int((u_int)ws.ws_col); 1906 packet_put_int((u_int)ws.ws_row); 1907 packet_put_int((u_int)ws.ws_xpixel); 1908 packet_put_int((u_int)ws.ws_ypixel); 1909 tio = get_saved_tio(); 1910 tty_make_modes(-1, tiop != NULL ? tiop : &tio); 1911 packet_send(); 1912 /* XXX wait for reply */ 1913 c->client_tty = 1; 1914 } 1915 1916 /* Transfer any environment variables from client to server */ 1917 if (options.num_send_env != 0 && env != NULL) { 1918 int i, j, matched; 1919 char *name, *val; 1920 1921 debug("Sending environment."); 1922 for (i = 0; env[i] != NULL; i++) { 1923 /* Split */ 1924 name = xstrdup(env[i]); 1925 if ((val = strchr(name, '=')) == NULL) { 1926 xfree(name); 1927 continue; 1928 } 1929 *val++ = '\0'; 1930 1931 matched = 0; 1932 for (j = 0; j < options.num_send_env; j++) { 1933 if (match_pattern(name, options.send_env[j])) { 1934 matched = 1; 1935 break; 1936 } 1937 } 1938 if (!matched) { 1939 debug3("Ignored env %s", name); 1940 xfree(name); 1941 continue; 1942 } 1943 1944 debug("Sending env %s = %s", name, val); 1945 channel_request_start(id, "env", 0); 1946 packet_put_cstring(name); 1947 packet_put_cstring(val); 1948 packet_send(); 1949 xfree(name); 1950 } 1951 } 1952 1953 len = buffer_len(cmd); 1954 if (len > 0) { 1955 if (len > 900) 1956 len = 900; 1957 if (want_subsystem) { 1958 debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd)); 1959 channel_request_start(id, "subsystem", subsys_repl != NULL); 1960 if (subsys_repl != NULL) { 1961 /* register callback for reply */ 1962 /* XXX we assume that client_loop has already been called */ 1963 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl); 1964 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl); 1965 } 1966 } else { 1967 debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd)); 1968 channel_request_start(id, "exec", 0); 1969 } 1970 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1971 packet_send(); 1972 } else { 1973 channel_request_start(id, "shell", 0); 1974 packet_send(); 1975 } 1976 } 1977 1978 static void 1979 client_init_dispatch_20(void) 1980 { 1981 dispatch_init(&dispatch_protocol_error); 1982 1983 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1984 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1985 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1986 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1987 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1988 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1989 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1990 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1991 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1992 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1993 1994 /* rekeying */ 1995 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1996 1997 /* global request reply messages */ 1998 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 1999 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2000 } 2001 static void 2002 client_init_dispatch_13(void) 2003 { 2004 dispatch_init(NULL); 2005 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 2006 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 2007 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2008 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2009 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2010 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2011 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2012 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2013 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2014 2015 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2016 &client_input_agent_open : &deny_input_open); 2017 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2018 &x11_input_open : &deny_input_open); 2019 } 2020 static void 2021 client_init_dispatch_15(void) 2022 { 2023 client_init_dispatch_13(); 2024 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2025 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2026 } 2027 static void 2028 client_init_dispatch(void) 2029 { 2030 if (compat20) 2031 client_init_dispatch_20(); 2032 else if (compat13) 2033 client_init_dispatch_13(); 2034 else 2035 client_init_dispatch_15(); 2036 } 2037 2038 /* client specific fatal cleanup */ 2039 void 2040 cleanup_exit(int i) 2041 { 2042 leave_raw_mode(); 2043 leave_non_blocking(); 2044 if (options.control_path != NULL && control_fd != -1) 2045 unlink(options.control_path); 2046 _exit(i); 2047 } 2048