1 /* $OpenBSD: clientloop.c,v 1.177 2007/01/21 01:41:54 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 63 #include <sys/types.h> 64 #include <sys/ioctl.h> 65 #include <sys/stat.h> 66 #include <sys/socket.h> 67 #include <sys/time.h> 68 #include <sys/param.h> 69 70 #include <ctype.h> 71 #include <errno.h> 72 #include <paths.h> 73 #include <signal.h> 74 #include <stdio.h> 75 #include <stdlib.h> 76 #include <string.h> 77 #include <termios.h> 78 #include <pwd.h> 79 #include <unistd.h> 80 81 #include "xmalloc.h" 82 #include "ssh.h" 83 #include "ssh1.h" 84 #include "ssh2.h" 85 #include "packet.h" 86 #include "buffer.h" 87 #include "compat.h" 88 #include "channels.h" 89 #include "dispatch.h" 90 #include "key.h" 91 #include "cipher.h" 92 #include "kex.h" 93 #include "log.h" 94 #include "readconf.h" 95 #include "clientloop.h" 96 #include "sshconnect.h" 97 #include "authfd.h" 98 #include "atomicio.h" 99 #include "sshpty.h" 100 #include "misc.h" 101 #include "monitor_fdpass.h" 102 #include "match.h" 103 #include "msg.h" 104 105 /* import options */ 106 extern Options options; 107 108 /* Flag indicating that stdin should be redirected from /dev/null. */ 109 extern int stdin_null_flag; 110 111 /* Flag indicating that no shell has been requested */ 112 extern int no_shell_flag; 113 114 /* Control socket */ 115 extern int control_fd; 116 117 /* 118 * Name of the host we are connecting to. This is the name given on the 119 * command line, or the HostName specified for the user-supplied name in a 120 * configuration file. 121 */ 122 extern char *host; 123 124 /* 125 * Flag to indicate that we have received a window change signal which has 126 * not yet been processed. This will cause a message indicating the new 127 * window size to be sent to the server a little later. This is volatile 128 * because this is updated in a signal handler. 129 */ 130 static volatile sig_atomic_t received_window_change_signal = 0; 131 static volatile sig_atomic_t received_signal = 0; 132 133 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 134 static int in_non_blocking_mode = 0; 135 136 /* Common data for the client loop code. */ 137 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 138 static int escape_char; /* Escape character. */ 139 static int escape_pending; /* Last character was the escape character */ 140 static int last_was_cr; /* Last character was a newline. */ 141 static int exit_status; /* Used to store the exit status of the command. */ 142 static int stdin_eof; /* EOF has been encountered on standard error. */ 143 static Buffer stdin_buffer; /* Buffer for stdin data. */ 144 static Buffer stdout_buffer; /* Buffer for stdout data. */ 145 static Buffer stderr_buffer; /* Buffer for stderr data. */ 146 static u_long stdin_bytes, stdout_bytes, stderr_bytes; 147 static u_int buffer_high;/* Soft max buffer size. */ 148 static int connection_in; /* Connection to server (input). */ 149 static int connection_out; /* Connection to server (output). */ 150 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 151 static int session_closed = 0; /* In SSH2: login session closed. */ 152 static int server_alive_timeouts = 0; 153 154 static void client_init_dispatch(void); 155 int session_ident = -1; 156 157 struct confirm_ctx { 158 int want_tty; 159 int want_subsys; 160 int want_x_fwd; 161 int want_agent_fwd; 162 Buffer cmd; 163 char *term; 164 struct termios tio; 165 char **env; 166 }; 167 168 /*XXX*/ 169 extern Kex *xxx_kex; 170 171 void ssh_process_session2_setup(int, int, int, Buffer *); 172 173 /* Restores stdin to blocking mode. */ 174 175 static void 176 leave_non_blocking(void) 177 { 178 if (in_non_blocking_mode) { 179 unset_nonblock(fileno(stdin)); 180 in_non_blocking_mode = 0; 181 } 182 } 183 184 /* Puts stdin terminal in non-blocking mode. */ 185 186 static void 187 enter_non_blocking(void) 188 { 189 in_non_blocking_mode = 1; 190 set_nonblock(fileno(stdin)); 191 } 192 193 /* 194 * Signal handler for the window change signal (SIGWINCH). This just sets a 195 * flag indicating that the window has changed. 196 */ 197 /*ARGSUSED */ 198 static void 199 window_change_handler(int sig) 200 { 201 received_window_change_signal = 1; 202 signal(SIGWINCH, window_change_handler); 203 } 204 205 /* 206 * Signal handler for signals that cause the program to terminate. These 207 * signals must be trapped to restore terminal modes. 208 */ 209 /*ARGSUSED */ 210 static void 211 signal_handler(int sig) 212 { 213 received_signal = sig; 214 quit_pending = 1; 215 } 216 217 /* 218 * Returns current time in seconds from Jan 1, 1970 with the maximum 219 * available resolution. 220 */ 221 222 static double 223 get_current_time(void) 224 { 225 struct timeval tv; 226 gettimeofday(&tv, NULL); 227 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 228 } 229 230 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 231 void 232 client_x11_get_proto(const char *display, const char *xauth_path, 233 u_int trusted, char **_proto, char **_data) 234 { 235 char cmd[1024]; 236 char line[512]; 237 char xdisplay[512]; 238 static char proto[512], data[512]; 239 FILE *f; 240 int got_data = 0, generated = 0, do_unlink = 0, i; 241 char *xauthdir, *xauthfile; 242 struct stat st; 243 244 xauthdir = xauthfile = NULL; 245 *_proto = proto; 246 *_data = data; 247 proto[0] = data[0] = '\0'; 248 249 if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) { 250 debug("No xauth program."); 251 } else { 252 if (display == NULL) { 253 debug("x11_get_proto: DISPLAY not set"); 254 return; 255 } 256 /* 257 * Handle FamilyLocal case where $DISPLAY does 258 * not match an authorization entry. For this we 259 * just try "xauth list unix:displaynum.screennum". 260 * XXX: "localhost" match to determine FamilyLocal 261 * is not perfect. 262 */ 263 if (strncmp(display, "localhost:", 10) == 0) { 264 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 265 display + 10); 266 display = xdisplay; 267 } 268 if (trusted == 0) { 269 xauthdir = xmalloc(MAXPATHLEN); 270 xauthfile = xmalloc(MAXPATHLEN); 271 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 272 if (mkdtemp(xauthdir) != NULL) { 273 do_unlink = 1; 274 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 275 xauthdir); 276 snprintf(cmd, sizeof(cmd), 277 "%s -f %s generate %s " SSH_X11_PROTO 278 " untrusted timeout 1200 2>" _PATH_DEVNULL, 279 xauth_path, xauthfile, display); 280 debug2("x11_get_proto: %s", cmd); 281 if (system(cmd) == 0) 282 generated = 1; 283 } 284 } 285 snprintf(cmd, sizeof(cmd), 286 "%s %s%s list %s 2>" _PATH_DEVNULL, 287 xauth_path, 288 generated ? "-f " : "" , 289 generated ? xauthfile : "", 290 display); 291 debug2("x11_get_proto: %s", cmd); 292 f = popen(cmd, "r"); 293 if (f && fgets(line, sizeof(line), f) && 294 sscanf(line, "%*s %511s %511s", proto, data) == 2) 295 got_data = 1; 296 if (f) 297 pclose(f); 298 } 299 300 if (do_unlink) { 301 unlink(xauthfile); 302 rmdir(xauthdir); 303 } 304 if (xauthdir) 305 xfree(xauthdir); 306 if (xauthfile) 307 xfree(xauthfile); 308 309 /* 310 * If we didn't get authentication data, just make up some 311 * data. The forwarding code will check the validity of the 312 * response anyway, and substitute this data. The X11 313 * server, however, will ignore this fake data and use 314 * whatever authentication mechanisms it was using otherwise 315 * for the local connection. 316 */ 317 if (!got_data) { 318 u_int32_t rnd = 0; 319 320 logit("Warning: No xauth data; " 321 "using fake authentication data for X11 forwarding."); 322 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 323 for (i = 0; i < 16; i++) { 324 if (i % 4 == 0) 325 rnd = arc4random(); 326 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 327 rnd & 0xff); 328 rnd >>= 8; 329 } 330 } 331 } 332 333 /* 334 * This is called when the interactive is entered. This checks if there is 335 * an EOF coming on stdin. We must check this explicitly, as select() does 336 * not appear to wake up when redirecting from /dev/null. 337 */ 338 339 static void 340 client_check_initial_eof_on_stdin(void) 341 { 342 int len; 343 char buf[1]; 344 345 /* 346 * If standard input is to be "redirected from /dev/null", we simply 347 * mark that we have seen an EOF and send an EOF message to the 348 * server. Otherwise, we try to read a single character; it appears 349 * that for some files, such /dev/null, select() never wakes up for 350 * read for this descriptor, which means that we never get EOF. This 351 * way we will get the EOF if stdin comes from /dev/null or similar. 352 */ 353 if (stdin_null_flag) { 354 /* Fake EOF on stdin. */ 355 debug("Sending eof."); 356 stdin_eof = 1; 357 packet_start(SSH_CMSG_EOF); 358 packet_send(); 359 } else { 360 enter_non_blocking(); 361 362 /* Check for immediate EOF on stdin. */ 363 len = read(fileno(stdin), buf, 1); 364 if (len == 0) { 365 /* EOF. Record that we have seen it and send EOF to server. */ 366 debug("Sending eof."); 367 stdin_eof = 1; 368 packet_start(SSH_CMSG_EOF); 369 packet_send(); 370 } else if (len > 0) { 371 /* 372 * Got data. We must store the data in the buffer, 373 * and also process it as an escape character if 374 * appropriate. 375 */ 376 if ((u_char) buf[0] == escape_char) 377 escape_pending = 1; 378 else 379 buffer_append(&stdin_buffer, buf, 1); 380 } 381 leave_non_blocking(); 382 } 383 } 384 385 386 /* 387 * Make packets from buffered stdin data, and buffer them for sending to the 388 * connection. 389 */ 390 391 static void 392 client_make_packets_from_stdin_data(void) 393 { 394 u_int len; 395 396 /* Send buffered stdin data to the server. */ 397 while (buffer_len(&stdin_buffer) > 0 && 398 packet_not_very_much_data_to_write()) { 399 len = buffer_len(&stdin_buffer); 400 /* Keep the packets at reasonable size. */ 401 if (len > packet_get_maxsize()) 402 len = packet_get_maxsize(); 403 packet_start(SSH_CMSG_STDIN_DATA); 404 packet_put_string(buffer_ptr(&stdin_buffer), len); 405 packet_send(); 406 buffer_consume(&stdin_buffer, len); 407 stdin_bytes += len; 408 /* If we have a pending EOF, send it now. */ 409 if (stdin_eof && buffer_len(&stdin_buffer) == 0) { 410 packet_start(SSH_CMSG_EOF); 411 packet_send(); 412 } 413 } 414 } 415 416 /* 417 * Checks if the client window has changed, and sends a packet about it to 418 * the server if so. The actual change is detected elsewhere (by a software 419 * interrupt on Unix); this just checks the flag and sends a message if 420 * appropriate. 421 */ 422 423 static void 424 client_check_window_change(void) 425 { 426 struct winsize ws; 427 428 if (! received_window_change_signal) 429 return; 430 /** XXX race */ 431 received_window_change_signal = 0; 432 433 debug2("client_check_window_change: changed"); 434 435 if (compat20) { 436 channel_send_window_changes(); 437 } else { 438 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 439 return; 440 packet_start(SSH_CMSG_WINDOW_SIZE); 441 packet_put_int((u_int)ws.ws_row); 442 packet_put_int((u_int)ws.ws_col); 443 packet_put_int((u_int)ws.ws_xpixel); 444 packet_put_int((u_int)ws.ws_ypixel); 445 packet_send(); 446 } 447 } 448 449 static void 450 client_global_request_reply(int type, u_int32_t seq, void *ctxt) 451 { 452 server_alive_timeouts = 0; 453 client_global_request_reply_fwd(type, seq, ctxt); 454 } 455 456 static void 457 server_alive_check(void) 458 { 459 if (++server_alive_timeouts > options.server_alive_count_max) { 460 logit("Timeout, server not responding."); 461 cleanup_exit(255); 462 } 463 packet_start(SSH2_MSG_GLOBAL_REQUEST); 464 packet_put_cstring("keepalive@openssh.com"); 465 packet_put_char(1); /* boolean: want reply */ 466 packet_send(); 467 } 468 469 /* 470 * Waits until the client can do something (some data becomes available on 471 * one of the file descriptors). 472 */ 473 static void 474 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 475 int *maxfdp, u_int *nallocp, int rekeying) 476 { 477 struct timeval tv, *tvp; 478 int ret; 479 480 /* Add any selections by the channel mechanism. */ 481 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); 482 483 if (!compat20) { 484 /* Read from the connection, unless our buffers are full. */ 485 if (buffer_len(&stdout_buffer) < buffer_high && 486 buffer_len(&stderr_buffer) < buffer_high && 487 channel_not_very_much_buffered_data()) 488 FD_SET(connection_in, *readsetp); 489 /* 490 * Read from stdin, unless we have seen EOF or have very much 491 * buffered data to send to the server. 492 */ 493 if (!stdin_eof && packet_not_very_much_data_to_write()) 494 FD_SET(fileno(stdin), *readsetp); 495 496 /* Select stdout/stderr if have data in buffer. */ 497 if (buffer_len(&stdout_buffer) > 0) 498 FD_SET(fileno(stdout), *writesetp); 499 if (buffer_len(&stderr_buffer) > 0) 500 FD_SET(fileno(stderr), *writesetp); 501 } else { 502 /* channel_prepare_select could have closed the last channel */ 503 if (session_closed && !channel_still_open() && 504 !packet_have_data_to_write()) { 505 /* clear mask since we did not call select() */ 506 memset(*readsetp, 0, *nallocp); 507 memset(*writesetp, 0, *nallocp); 508 return; 509 } else { 510 FD_SET(connection_in, *readsetp); 511 } 512 } 513 514 /* Select server connection if have data to write to the server. */ 515 if (packet_have_data_to_write()) 516 FD_SET(connection_out, *writesetp); 517 518 if (control_fd != -1) 519 FD_SET(control_fd, *readsetp); 520 521 /* 522 * Wait for something to happen. This will suspend the process until 523 * some selected descriptor can be read, written, or has some other 524 * event pending. 525 */ 526 527 if (options.server_alive_interval == 0 || !compat20) 528 tvp = NULL; 529 else { 530 tv.tv_sec = options.server_alive_interval; 531 tv.tv_usec = 0; 532 tvp = &tv; 533 } 534 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 535 if (ret < 0) { 536 char buf[100]; 537 538 /* 539 * We have to clear the select masks, because we return. 540 * We have to return, because the mainloop checks for the flags 541 * set by the signal handlers. 542 */ 543 memset(*readsetp, 0, *nallocp); 544 memset(*writesetp, 0, *nallocp); 545 546 if (errno == EINTR) 547 return; 548 /* Note: we might still have data in the buffers. */ 549 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 550 buffer_append(&stderr_buffer, buf, strlen(buf)); 551 quit_pending = 1; 552 } else if (ret == 0) 553 server_alive_check(); 554 } 555 556 static void 557 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 558 { 559 /* Flush stdout and stderr buffers. */ 560 if (buffer_len(bout) > 0) 561 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout)); 562 if (buffer_len(berr) > 0) 563 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr)); 564 565 leave_raw_mode(); 566 567 /* 568 * Free (and clear) the buffer to reduce the amount of data that gets 569 * written to swap. 570 */ 571 buffer_free(bin); 572 buffer_free(bout); 573 buffer_free(berr); 574 575 /* Send the suspend signal to the program itself. */ 576 kill(getpid(), SIGTSTP); 577 578 /* Reset window sizes in case they have changed */ 579 received_window_change_signal = 1; 580 581 /* OK, we have been continued by the user. Reinitialize buffers. */ 582 buffer_init(bin); 583 buffer_init(bout); 584 buffer_init(berr); 585 586 enter_raw_mode(); 587 } 588 589 static void 590 client_process_net_input(fd_set *readset) 591 { 592 int len; 593 char buf[8192]; 594 595 /* 596 * Read input from the server, and add any such data to the buffer of 597 * the packet subsystem. 598 */ 599 if (FD_ISSET(connection_in, readset)) { 600 /* Read as much as possible. */ 601 len = read(connection_in, buf, sizeof(buf)); 602 if (len == 0) { 603 /* Received EOF. The remote host has closed the connection. */ 604 snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", 605 host); 606 buffer_append(&stderr_buffer, buf, strlen(buf)); 607 quit_pending = 1; 608 return; 609 } 610 /* 611 * There is a kernel bug on Solaris that causes select to 612 * sometimes wake up even though there is no data available. 613 */ 614 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 615 len = 0; 616 617 if (len < 0) { 618 /* An error has encountered. Perhaps there is a network problem. */ 619 snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", 620 host, strerror(errno)); 621 buffer_append(&stderr_buffer, buf, strlen(buf)); 622 quit_pending = 1; 623 return; 624 } 625 packet_process_incoming(buf, len); 626 } 627 } 628 629 static void 630 client_subsystem_reply(int type, u_int32_t seq, void *ctxt) 631 { 632 int id; 633 Channel *c; 634 635 id = packet_get_int(); 636 packet_check_eom(); 637 638 if ((c = channel_lookup(id)) == NULL) { 639 error("%s: no channel for id %d", __func__, id); 640 return; 641 } 642 643 if (type == SSH2_MSG_CHANNEL_SUCCESS) 644 debug2("Request suceeded on channel %d", id); 645 else if (type == SSH2_MSG_CHANNEL_FAILURE) { 646 error("Request failed on channel %d", id); 647 channel_free(c); 648 } 649 } 650 651 static void 652 client_extra_session2_setup(int id, void *arg) 653 { 654 struct confirm_ctx *cctx = arg; 655 const char *display; 656 Channel *c; 657 int i; 658 659 if (cctx == NULL) 660 fatal("%s: cctx == NULL", __func__); 661 if ((c = channel_lookup(id)) == NULL) 662 fatal("%s: no channel for id %d", __func__, id); 663 664 display = getenv("DISPLAY"); 665 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) { 666 char *proto, *data; 667 /* Get reasonable local authentication information. */ 668 client_x11_get_proto(display, options.xauth_location, 669 options.forward_x11_trusted, &proto, &data); 670 /* Request forwarding with authentication spoofing. */ 671 debug("Requesting X11 forwarding with authentication spoofing."); 672 x11_request_forwarding_with_spoofing(id, display, proto, data); 673 /* XXX wait for reply */ 674 } 675 676 if (cctx->want_agent_fwd && options.forward_agent) { 677 debug("Requesting authentication agent forwarding."); 678 channel_request_start(id, "auth-agent-req@openssh.com", 0); 679 packet_send(); 680 } 681 682 client_session2_setup(id, cctx->want_tty, cctx->want_subsys, 683 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env, 684 client_subsystem_reply); 685 686 c->confirm_ctx = NULL; 687 buffer_free(&cctx->cmd); 688 xfree(cctx->term); 689 if (cctx->env != NULL) { 690 for (i = 0; cctx->env[i] != NULL; i++) 691 xfree(cctx->env[i]); 692 xfree(cctx->env); 693 } 694 xfree(cctx); 695 } 696 697 static void 698 client_process_control(fd_set *readset) 699 { 700 Buffer m; 701 Channel *c; 702 int client_fd, new_fd[3], ver, allowed; 703 socklen_t addrlen; 704 struct sockaddr_storage addr; 705 struct confirm_ctx *cctx; 706 char *cmd; 707 u_int i, len, env_len, command, flags; 708 uid_t euid; 709 gid_t egid; 710 711 /* 712 * Accept connection on control socket 713 */ 714 if (control_fd == -1 || !FD_ISSET(control_fd, readset)) 715 return; 716 717 memset(&addr, 0, sizeof(addr)); 718 addrlen = sizeof(addr); 719 if ((client_fd = accept(control_fd, 720 (struct sockaddr*)&addr, &addrlen)) == -1) { 721 error("%s accept: %s", __func__, strerror(errno)); 722 return; 723 } 724 725 if (getpeereid(client_fd, &euid, &egid) < 0) { 726 error("%s getpeereid failed: %s", __func__, strerror(errno)); 727 close(client_fd); 728 return; 729 } 730 if ((euid != 0) && (getuid() != euid)) { 731 error("control mode uid mismatch: peer euid %u != uid %u", 732 (u_int) euid, (u_int) getuid()); 733 close(client_fd); 734 return; 735 } 736 737 unset_nonblock(client_fd); 738 739 /* Read command */ 740 buffer_init(&m); 741 if (ssh_msg_recv(client_fd, &m) == -1) { 742 error("%s: client msg_recv failed", __func__); 743 close(client_fd); 744 buffer_free(&m); 745 return; 746 } 747 if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { 748 error("%s: wrong client version %d", __func__, ver); 749 buffer_free(&m); 750 close(client_fd); 751 return; 752 } 753 754 allowed = 1; 755 command = buffer_get_int(&m); 756 flags = buffer_get_int(&m); 757 758 buffer_clear(&m); 759 760 switch (command) { 761 case SSHMUX_COMMAND_OPEN: 762 if (options.control_master == SSHCTL_MASTER_ASK || 763 options.control_master == SSHCTL_MASTER_AUTO_ASK) 764 allowed = ask_permission("Allow shared connection " 765 "to %s? ", host); 766 /* continue below */ 767 break; 768 case SSHMUX_COMMAND_TERMINATE: 769 if (options.control_master == SSHCTL_MASTER_ASK || 770 options.control_master == SSHCTL_MASTER_AUTO_ASK) 771 allowed = ask_permission("Terminate shared connection " 772 "to %s? ", host); 773 if (allowed) 774 quit_pending = 1; 775 /* FALLTHROUGH */ 776 case SSHMUX_COMMAND_ALIVE_CHECK: 777 /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */ 778 buffer_clear(&m); 779 buffer_put_int(&m, allowed); 780 buffer_put_int(&m, getpid()); 781 if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { 782 error("%s: client msg_send failed", __func__); 783 close(client_fd); 784 buffer_free(&m); 785 return; 786 } 787 buffer_free(&m); 788 close(client_fd); 789 return; 790 default: 791 error("Unsupported command %d", command); 792 buffer_free(&m); 793 close(client_fd); 794 return; 795 } 796 797 /* Reply for SSHMUX_COMMAND_OPEN */ 798 buffer_clear(&m); 799 buffer_put_int(&m, allowed); 800 buffer_put_int(&m, getpid()); 801 if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { 802 error("%s: client msg_send failed", __func__); 803 close(client_fd); 804 buffer_free(&m); 805 return; 806 } 807 808 if (!allowed) { 809 error("Refused control connection"); 810 close(client_fd); 811 buffer_free(&m); 812 return; 813 } 814 815 buffer_clear(&m); 816 if (ssh_msg_recv(client_fd, &m) == -1) { 817 error("%s: client msg_recv failed", __func__); 818 close(client_fd); 819 buffer_free(&m); 820 return; 821 } 822 if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { 823 error("%s: wrong client version %d", __func__, ver); 824 buffer_free(&m); 825 close(client_fd); 826 return; 827 } 828 829 cctx = xcalloc(1, sizeof(*cctx)); 830 cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0; 831 cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0; 832 cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0; 833 cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0; 834 cctx->term = buffer_get_string(&m, &len); 835 836 cmd = buffer_get_string(&m, &len); 837 buffer_init(&cctx->cmd); 838 buffer_append(&cctx->cmd, cmd, strlen(cmd)); 839 840 env_len = buffer_get_int(&m); 841 env_len = MIN(env_len, 4096); 842 debug3("%s: receiving %d env vars", __func__, env_len); 843 if (env_len != 0) { 844 cctx->env = xcalloc(env_len + 1, sizeof(*cctx->env)); 845 for (i = 0; i < env_len; i++) 846 cctx->env[i] = buffer_get_string(&m, &len); 847 cctx->env[i] = NULL; 848 } 849 850 debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__, 851 cctx->want_tty, cctx->want_subsys, cmd); 852 xfree(cmd); 853 854 /* Gather fds from client */ 855 new_fd[0] = mm_receive_fd(client_fd); 856 new_fd[1] = mm_receive_fd(client_fd); 857 new_fd[2] = mm_receive_fd(client_fd); 858 859 debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__, 860 new_fd[0], new_fd[1], new_fd[2]); 861 862 /* Try to pick up ttymodes from client before it goes raw */ 863 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1) 864 error("%s: tcgetattr: %s", __func__, strerror(errno)); 865 866 /* This roundtrip is just for synchronisation of ttymodes */ 867 buffer_clear(&m); 868 if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { 869 error("%s: client msg_send failed", __func__); 870 close(client_fd); 871 close(new_fd[0]); 872 close(new_fd[1]); 873 close(new_fd[2]); 874 buffer_free(&m); 875 xfree(cctx->term); 876 if (env_len != 0) { 877 for (i = 0; i < env_len; i++) 878 xfree(cctx->env[i]); 879 xfree(cctx->env); 880 } 881 return; 882 } 883 buffer_free(&m); 884 885 /* enable nonblocking unless tty */ 886 if (!isatty(new_fd[0])) 887 set_nonblock(new_fd[0]); 888 if (!isatty(new_fd[1])) 889 set_nonblock(new_fd[1]); 890 if (!isatty(new_fd[2])) 891 set_nonblock(new_fd[2]); 892 893 set_nonblock(client_fd); 894 895 c = channel_new("session", SSH_CHANNEL_OPENING, 896 new_fd[0], new_fd[1], new_fd[2], 897 CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT, 898 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 899 900 /* XXX */ 901 c->ctl_fd = client_fd; 902 903 debug3("%s: channel_new: %d", __func__, c->self); 904 905 channel_send_open(c->self); 906 channel_register_confirm(c->self, client_extra_session2_setup, cctx); 907 } 908 909 static void 910 process_cmdline(void) 911 { 912 void (*handler)(int); 913 char *s, *cmd, *cancel_host; 914 int delete = 0; 915 int local = 0; 916 u_short cancel_port; 917 Forward fwd; 918 919 leave_raw_mode(); 920 handler = signal(SIGINT, SIG_IGN); 921 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 922 if (s == NULL) 923 goto out; 924 while (*s && isspace(*s)) 925 s++; 926 if (*s == '-') 927 s++; /* Skip cmdline '-', if any */ 928 if (*s == '\0') 929 goto out; 930 931 if (*s == 'h' || *s == 'H' || *s == '?') { 932 logit("Commands:"); 933 logit(" -L[bind_address:]port:host:hostport " 934 "Request local forward"); 935 logit(" -R[bind_address:]port:host:hostport " 936 "Request remote forward"); 937 logit(" -KR[bind_address:]port " 938 "Cancel remote forward"); 939 if (!options.permit_local_command) 940 goto out; 941 logit(" !args " 942 "Execute local command"); 943 goto out; 944 } 945 946 if (*s == '!' && options.permit_local_command) { 947 s++; 948 ssh_local_cmd(s); 949 goto out; 950 } 951 952 if (*s == 'K') { 953 delete = 1; 954 s++; 955 } 956 if (*s != 'L' && *s != 'R') { 957 logit("Invalid command."); 958 goto out; 959 } 960 if (*s == 'L') 961 local = 1; 962 if (local && delete) { 963 logit("Not supported."); 964 goto out; 965 } 966 if ((!local || delete) && !compat20) { 967 logit("Not supported for SSH protocol version 1."); 968 goto out; 969 } 970 971 s++; 972 while (*s && isspace(*s)) 973 s++; 974 975 if (delete) { 976 cancel_port = 0; 977 cancel_host = hpdelim(&s); /* may be NULL */ 978 if (s != NULL) { 979 cancel_port = a2port(s); 980 cancel_host = cleanhostname(cancel_host); 981 } else { 982 cancel_port = a2port(cancel_host); 983 cancel_host = NULL; 984 } 985 if (cancel_port == 0) { 986 logit("Bad forwarding close port"); 987 goto out; 988 } 989 channel_request_rforward_cancel(cancel_host, cancel_port); 990 } else { 991 if (!parse_forward(&fwd, s)) { 992 logit("Bad forwarding specification."); 993 goto out; 994 } 995 if (local) { 996 if (channel_setup_local_fwd_listener(fwd.listen_host, 997 fwd.listen_port, fwd.connect_host, 998 fwd.connect_port, options.gateway_ports) < 0) { 999 logit("Port forwarding failed."); 1000 goto out; 1001 } 1002 } else { 1003 if (channel_request_remote_forwarding(fwd.listen_host, 1004 fwd.listen_port, fwd.connect_host, 1005 fwd.connect_port) < 0) { 1006 logit("Port forwarding failed."); 1007 goto out; 1008 } 1009 } 1010 1011 logit("Forwarding port."); 1012 } 1013 1014 out: 1015 signal(SIGINT, handler); 1016 enter_raw_mode(); 1017 if (cmd) 1018 xfree(cmd); 1019 } 1020 1021 /* process the characters one by one */ 1022 static int 1023 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) 1024 { 1025 char string[1024]; 1026 pid_t pid; 1027 int bytes = 0; 1028 u_int i; 1029 u_char ch; 1030 char *s; 1031 1032 if (len <= 0) 1033 return (0); 1034 1035 for (i = 0; i < (u_int)len; i++) { 1036 /* Get one character at a time. */ 1037 ch = buf[i]; 1038 1039 if (escape_pending) { 1040 /* We have previously seen an escape character. */ 1041 /* Clear the flag now. */ 1042 escape_pending = 0; 1043 1044 /* Process the escaped character. */ 1045 switch (ch) { 1046 case '.': 1047 /* Terminate the connection. */ 1048 snprintf(string, sizeof string, "%c.\r\n", escape_char); 1049 buffer_append(berr, string, strlen(string)); 1050 1051 quit_pending = 1; 1052 return -1; 1053 1054 case 'Z' - 64: 1055 /* Suspend the program. */ 1056 /* Print a message to that effect to the user. */ 1057 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); 1058 buffer_append(berr, string, strlen(string)); 1059 1060 /* Restore terminal modes and suspend. */ 1061 client_suspend_self(bin, bout, berr); 1062 1063 /* We have been continued. */ 1064 continue; 1065 1066 case 'B': 1067 if (compat20) { 1068 snprintf(string, sizeof string, 1069 "%cB\r\n", escape_char); 1070 buffer_append(berr, string, 1071 strlen(string)); 1072 channel_request_start(session_ident, 1073 "break", 0); 1074 packet_put_int(1000); 1075 packet_send(); 1076 } 1077 continue; 1078 1079 case 'R': 1080 if (compat20) { 1081 if (datafellows & SSH_BUG_NOREKEY) 1082 logit("Server does not support re-keying"); 1083 else 1084 need_rekeying = 1; 1085 } 1086 continue; 1087 1088 case '&': 1089 /* 1090 * Detach the program (continue to serve connections, 1091 * but put in background and no more new connections). 1092 */ 1093 /* Restore tty modes. */ 1094 leave_raw_mode(); 1095 1096 /* Stop listening for new connections. */ 1097 channel_stop_listening(); 1098 1099 snprintf(string, sizeof string, 1100 "%c& [backgrounded]\n", escape_char); 1101 buffer_append(berr, string, strlen(string)); 1102 1103 /* Fork into background. */ 1104 pid = fork(); 1105 if (pid < 0) { 1106 error("fork: %.100s", strerror(errno)); 1107 continue; 1108 } 1109 if (pid != 0) { /* This is the parent. */ 1110 /* The parent just exits. */ 1111 exit(0); 1112 } 1113 /* The child continues serving connections. */ 1114 if (compat20) { 1115 buffer_append(bin, "\004", 1); 1116 /* fake EOF on stdin */ 1117 return -1; 1118 } else if (!stdin_eof) { 1119 /* 1120 * Sending SSH_CMSG_EOF alone does not always appear 1121 * to be enough. So we try to send an EOF character 1122 * first. 1123 */ 1124 packet_start(SSH_CMSG_STDIN_DATA); 1125 packet_put_string("\004", 1); 1126 packet_send(); 1127 /* Close stdin. */ 1128 stdin_eof = 1; 1129 if (buffer_len(bin) == 0) { 1130 packet_start(SSH_CMSG_EOF); 1131 packet_send(); 1132 } 1133 } 1134 continue; 1135 1136 case '?': 1137 snprintf(string, sizeof string, 1138 "%c?\r\n\ 1139 Supported escape sequences:\r\n\ 1140 %c. - terminate connection\r\n\ 1141 %cB - send a BREAK to the remote system\r\n\ 1142 %cC - open a command line\r\n\ 1143 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1144 %c^Z - suspend ssh\r\n\ 1145 %c# - list forwarded connections\r\n\ 1146 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1147 %c? - this message\r\n\ 1148 %c%c - send the escape character by typing it twice\r\n\ 1149 (Note that escapes are only recognized immediately after newline.)\r\n", 1150 escape_char, escape_char, escape_char, escape_char, 1151 escape_char, escape_char, escape_char, escape_char, 1152 escape_char, escape_char, escape_char); 1153 buffer_append(berr, string, strlen(string)); 1154 continue; 1155 1156 case '#': 1157 snprintf(string, sizeof string, "%c#\r\n", escape_char); 1158 buffer_append(berr, string, strlen(string)); 1159 s = channel_open_message(); 1160 buffer_append(berr, s, strlen(s)); 1161 xfree(s); 1162 continue; 1163 1164 case 'C': 1165 process_cmdline(); 1166 continue; 1167 1168 default: 1169 if (ch != escape_char) { 1170 buffer_put_char(bin, escape_char); 1171 bytes++; 1172 } 1173 /* Escaped characters fall through here */ 1174 break; 1175 } 1176 } else { 1177 /* 1178 * The previous character was not an escape char. Check if this 1179 * is an escape. 1180 */ 1181 if (last_was_cr && ch == escape_char) { 1182 /* It is. Set the flag and continue to next character. */ 1183 escape_pending = 1; 1184 continue; 1185 } 1186 } 1187 1188 /* 1189 * Normal character. Record whether it was a newline, 1190 * and append it to the buffer. 1191 */ 1192 last_was_cr = (ch == '\r' || ch == '\n'); 1193 buffer_put_char(bin, ch); 1194 bytes++; 1195 } 1196 return bytes; 1197 } 1198 1199 static void 1200 client_process_input(fd_set *readset) 1201 { 1202 int len; 1203 char buf[8192]; 1204 1205 /* Read input from stdin. */ 1206 if (FD_ISSET(fileno(stdin), readset)) { 1207 /* Read as much as possible. */ 1208 len = read(fileno(stdin), buf, sizeof(buf)); 1209 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 1210 return; /* we'll try again later */ 1211 if (len <= 0) { 1212 /* 1213 * Received EOF or error. They are treated 1214 * similarly, except that an error message is printed 1215 * if it was an error condition. 1216 */ 1217 if (len < 0) { 1218 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); 1219 buffer_append(&stderr_buffer, buf, strlen(buf)); 1220 } 1221 /* Mark that we have seen EOF. */ 1222 stdin_eof = 1; 1223 /* 1224 * Send an EOF message to the server unless there is 1225 * data in the buffer. If there is data in the 1226 * buffer, no message will be sent now. Code 1227 * elsewhere will send the EOF when the buffer 1228 * becomes empty if stdin_eof is set. 1229 */ 1230 if (buffer_len(&stdin_buffer) == 0) { 1231 packet_start(SSH_CMSG_EOF); 1232 packet_send(); 1233 } 1234 } else if (escape_char == SSH_ESCAPECHAR_NONE) { 1235 /* 1236 * Normal successful read, and no escape character. 1237 * Just append the data to buffer. 1238 */ 1239 buffer_append(&stdin_buffer, buf, len); 1240 } else { 1241 /* 1242 * Normal, successful read. But we have an escape character 1243 * and have to process the characters one by one. 1244 */ 1245 if (process_escapes(&stdin_buffer, &stdout_buffer, 1246 &stderr_buffer, buf, len) == -1) 1247 return; 1248 } 1249 } 1250 } 1251 1252 static void 1253 client_process_output(fd_set *writeset) 1254 { 1255 int len; 1256 char buf[100]; 1257 1258 /* Write buffered output to stdout. */ 1259 if (FD_ISSET(fileno(stdout), writeset)) { 1260 /* Write as much data as possible. */ 1261 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1262 buffer_len(&stdout_buffer)); 1263 if (len <= 0) { 1264 if (errno == EINTR || errno == EAGAIN) 1265 len = 0; 1266 else { 1267 /* 1268 * An error or EOF was encountered. Put an 1269 * error message to stderr buffer. 1270 */ 1271 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); 1272 buffer_append(&stderr_buffer, buf, strlen(buf)); 1273 quit_pending = 1; 1274 return; 1275 } 1276 } 1277 /* Consume printed data from the buffer. */ 1278 buffer_consume(&stdout_buffer, len); 1279 stdout_bytes += len; 1280 } 1281 /* Write buffered output to stderr. */ 1282 if (FD_ISSET(fileno(stderr), writeset)) { 1283 /* Write as much data as possible. */ 1284 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1285 buffer_len(&stderr_buffer)); 1286 if (len <= 0) { 1287 if (errno == EINTR || errno == EAGAIN) 1288 len = 0; 1289 else { 1290 /* EOF or error, but can't even print error message. */ 1291 quit_pending = 1; 1292 return; 1293 } 1294 } 1295 /* Consume printed characters from the buffer. */ 1296 buffer_consume(&stderr_buffer, len); 1297 stderr_bytes += len; 1298 } 1299 } 1300 1301 /* 1302 * Get packets from the connection input buffer, and process them as long as 1303 * there are packets available. 1304 * 1305 * Any unknown packets received during the actual 1306 * session cause the session to terminate. This is 1307 * intended to make debugging easier since no 1308 * confirmations are sent. Any compatible protocol 1309 * extensions must be negotiated during the 1310 * preparatory phase. 1311 */ 1312 1313 static void 1314 client_process_buffered_input_packets(void) 1315 { 1316 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL); 1317 } 1318 1319 /* scan buf[] for '~' before sending data to the peer */ 1320 1321 static int 1322 simple_escape_filter(Channel *c, char *buf, int len) 1323 { 1324 /* XXX we assume c->extended is writeable */ 1325 return process_escapes(&c->input, &c->output, &c->extended, buf, len); 1326 } 1327 1328 static void 1329 client_channel_closed(int id, void *arg) 1330 { 1331 channel_cancel_cleanup(id); 1332 session_closed = 1; 1333 leave_raw_mode(); 1334 } 1335 1336 /* 1337 * Implements the interactive session with the server. This is called after 1338 * the user has been authenticated, and a command has been started on the 1339 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1340 * used as an escape character for terminating or suspending the session. 1341 */ 1342 1343 int 1344 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1345 { 1346 fd_set *readset = NULL, *writeset = NULL; 1347 double start_time, total_time; 1348 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1349 u_int nalloc = 0; 1350 char buf[100]; 1351 1352 debug("Entering interactive session."); 1353 1354 start_time = get_current_time(); 1355 1356 /* Initialize variables. */ 1357 escape_pending = 0; 1358 last_was_cr = 1; 1359 exit_status = -1; 1360 stdin_eof = 0; 1361 buffer_high = 64 * 1024; 1362 connection_in = packet_get_connection_in(); 1363 connection_out = packet_get_connection_out(); 1364 max_fd = MAX(connection_in, connection_out); 1365 if (control_fd != -1) 1366 max_fd = MAX(max_fd, control_fd); 1367 1368 if (!compat20) { 1369 /* enable nonblocking unless tty */ 1370 if (!isatty(fileno(stdin))) 1371 set_nonblock(fileno(stdin)); 1372 if (!isatty(fileno(stdout))) 1373 set_nonblock(fileno(stdout)); 1374 if (!isatty(fileno(stderr))) 1375 set_nonblock(fileno(stderr)); 1376 max_fd = MAX(max_fd, fileno(stdin)); 1377 max_fd = MAX(max_fd, fileno(stdout)); 1378 max_fd = MAX(max_fd, fileno(stderr)); 1379 } 1380 stdin_bytes = 0; 1381 stdout_bytes = 0; 1382 stderr_bytes = 0; 1383 quit_pending = 0; 1384 escape_char = escape_char_arg; 1385 1386 /* Initialize buffers. */ 1387 buffer_init(&stdin_buffer); 1388 buffer_init(&stdout_buffer); 1389 buffer_init(&stderr_buffer); 1390 1391 client_init_dispatch(); 1392 1393 /* 1394 * Set signal handlers, (e.g. to restore non-blocking mode) 1395 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1396 */ 1397 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1398 signal(SIGHUP, signal_handler); 1399 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1400 signal(SIGINT, signal_handler); 1401 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1402 signal(SIGQUIT, signal_handler); 1403 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1404 signal(SIGTERM, signal_handler); 1405 signal(SIGWINCH, window_change_handler); 1406 1407 if (have_pty) 1408 enter_raw_mode(); 1409 1410 if (compat20) { 1411 session_ident = ssh2_chan_id; 1412 if (escape_char != SSH_ESCAPECHAR_NONE) 1413 channel_register_filter(session_ident, 1414 simple_escape_filter, NULL); 1415 if (session_ident != -1) 1416 channel_register_cleanup(session_ident, 1417 client_channel_closed, 0); 1418 } else { 1419 /* Check if we should immediately send eof on stdin. */ 1420 client_check_initial_eof_on_stdin(); 1421 } 1422 1423 /* Main loop of the client for the interactive session mode. */ 1424 while (!quit_pending) { 1425 1426 /* Process buffered packets sent by the server. */ 1427 client_process_buffered_input_packets(); 1428 1429 if (compat20 && session_closed && !channel_still_open()) 1430 break; 1431 1432 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1433 1434 if (rekeying) { 1435 debug("rekeying in progress"); 1436 } else { 1437 /* 1438 * Make packets of buffered stdin data, and buffer 1439 * them for sending to the server. 1440 */ 1441 if (!compat20) 1442 client_make_packets_from_stdin_data(); 1443 1444 /* 1445 * Make packets from buffered channel data, and 1446 * enqueue them for sending to the server. 1447 */ 1448 if (packet_not_very_much_data_to_write()) 1449 channel_output_poll(); 1450 1451 /* 1452 * Check if the window size has changed, and buffer a 1453 * message about it to the server if so. 1454 */ 1455 client_check_window_change(); 1456 1457 if (quit_pending) 1458 break; 1459 } 1460 /* 1461 * Wait until we have something to do (something becomes 1462 * available on one of the descriptors). 1463 */ 1464 max_fd2 = max_fd; 1465 client_wait_until_can_do_something(&readset, &writeset, 1466 &max_fd2, &nalloc, rekeying); 1467 1468 if (quit_pending) 1469 break; 1470 1471 /* Do channel operations unless rekeying in progress. */ 1472 if (!rekeying) { 1473 channel_after_select(readset, writeset); 1474 if (need_rekeying || packet_need_rekeying()) { 1475 debug("need rekeying"); 1476 xxx_kex->done = 0; 1477 kex_send_kexinit(xxx_kex); 1478 need_rekeying = 0; 1479 } 1480 } 1481 1482 /* Buffer input from the connection. */ 1483 client_process_net_input(readset); 1484 1485 /* Accept control connections. */ 1486 client_process_control(readset); 1487 1488 if (quit_pending) 1489 break; 1490 1491 if (!compat20) { 1492 /* Buffer data from stdin */ 1493 client_process_input(readset); 1494 /* 1495 * Process output to stdout and stderr. Output to 1496 * the connection is processed elsewhere (above). 1497 */ 1498 client_process_output(writeset); 1499 } 1500 1501 /* Send as much buffered packet data as possible to the sender. */ 1502 if (FD_ISSET(connection_out, writeset)) 1503 packet_write_poll(); 1504 } 1505 if (readset) 1506 xfree(readset); 1507 if (writeset) 1508 xfree(writeset); 1509 1510 /* Terminate the session. */ 1511 1512 /* Stop watching for window change. */ 1513 signal(SIGWINCH, SIG_DFL); 1514 1515 channel_free_all(); 1516 1517 if (have_pty) 1518 leave_raw_mode(); 1519 1520 /* restore blocking io */ 1521 if (!isatty(fileno(stdin))) 1522 unset_nonblock(fileno(stdin)); 1523 if (!isatty(fileno(stdout))) 1524 unset_nonblock(fileno(stdout)); 1525 if (!isatty(fileno(stderr))) 1526 unset_nonblock(fileno(stderr)); 1527 1528 /* 1529 * If there was no shell or command requested, there will be no remote 1530 * exit status to be returned. In that case, clear error code if the 1531 * connection was deliberately terminated at this end. 1532 */ 1533 if (no_shell_flag && received_signal == SIGTERM) { 1534 received_signal = 0; 1535 exit_status = 0; 1536 } 1537 1538 if (received_signal) 1539 fatal("Killed by signal %d.", (int) received_signal); 1540 1541 /* 1542 * In interactive mode (with pseudo tty) display a message indicating 1543 * that the connection has been closed. 1544 */ 1545 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1546 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); 1547 buffer_append(&stderr_buffer, buf, strlen(buf)); 1548 } 1549 1550 /* Output any buffered data for stdout. */ 1551 while (buffer_len(&stdout_buffer) > 0) { 1552 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1553 buffer_len(&stdout_buffer)); 1554 if (len <= 0) { 1555 error("Write failed flushing stdout buffer."); 1556 break; 1557 } 1558 buffer_consume(&stdout_buffer, len); 1559 stdout_bytes += len; 1560 } 1561 1562 /* Output any buffered data for stderr. */ 1563 while (buffer_len(&stderr_buffer) > 0) { 1564 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1565 buffer_len(&stderr_buffer)); 1566 if (len <= 0) { 1567 error("Write failed flushing stderr buffer."); 1568 break; 1569 } 1570 buffer_consume(&stderr_buffer, len); 1571 stderr_bytes += len; 1572 } 1573 1574 /* Clear and free any buffers. */ 1575 memset(buf, 0, sizeof(buf)); 1576 buffer_free(&stdin_buffer); 1577 buffer_free(&stdout_buffer); 1578 buffer_free(&stderr_buffer); 1579 1580 /* Report bytes transferred, and transfer rates. */ 1581 total_time = get_current_time() - start_time; 1582 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", 1583 stdin_bytes, stdout_bytes, stderr_bytes, total_time); 1584 if (total_time > 0) 1585 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", 1586 stdin_bytes / total_time, stdout_bytes / total_time, 1587 stderr_bytes / total_time); 1588 1589 /* Return the exit status of the program. */ 1590 debug("Exit status %d", exit_status); 1591 return exit_status; 1592 } 1593 1594 /*********/ 1595 1596 static void 1597 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1598 { 1599 u_int data_len; 1600 char *data = packet_get_string(&data_len); 1601 packet_check_eom(); 1602 buffer_append(&stdout_buffer, data, data_len); 1603 memset(data, 0, data_len); 1604 xfree(data); 1605 } 1606 static void 1607 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1608 { 1609 u_int data_len; 1610 char *data = packet_get_string(&data_len); 1611 packet_check_eom(); 1612 buffer_append(&stderr_buffer, data, data_len); 1613 memset(data, 0, data_len); 1614 xfree(data); 1615 } 1616 static void 1617 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1618 { 1619 exit_status = packet_get_int(); 1620 packet_check_eom(); 1621 /* Acknowledge the exit. */ 1622 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1623 packet_send(); 1624 /* 1625 * Must wait for packet to be sent since we are 1626 * exiting the loop. 1627 */ 1628 packet_write_wait(); 1629 /* Flag that we want to exit. */ 1630 quit_pending = 1; 1631 } 1632 static void 1633 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1634 { 1635 Channel *c = NULL; 1636 int remote_id, sock; 1637 1638 /* Read the remote channel number from the message. */ 1639 remote_id = packet_get_int(); 1640 packet_check_eom(); 1641 1642 /* 1643 * Get a connection to the local authentication agent (this may again 1644 * get forwarded). 1645 */ 1646 sock = ssh_get_authentication_socket(); 1647 1648 /* 1649 * If we could not connect the agent, send an error message back to 1650 * the server. This should never happen unless the agent dies, 1651 * because authentication forwarding is only enabled if we have an 1652 * agent. 1653 */ 1654 if (sock >= 0) { 1655 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1656 -1, 0, 0, 0, "authentication agent connection", 1); 1657 c->remote_id = remote_id; 1658 c->force_drain = 1; 1659 } 1660 if (c == NULL) { 1661 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1662 packet_put_int(remote_id); 1663 } else { 1664 /* Send a confirmation to the remote host. */ 1665 debug("Forwarding authentication connection."); 1666 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1667 packet_put_int(remote_id); 1668 packet_put_int(c->self); 1669 } 1670 packet_send(); 1671 } 1672 1673 static Channel * 1674 client_request_forwarded_tcpip(const char *request_type, int rchan) 1675 { 1676 Channel *c = NULL; 1677 char *listen_address, *originator_address; 1678 int listen_port, originator_port; 1679 int sock; 1680 1681 /* Get rest of the packet */ 1682 listen_address = packet_get_string(NULL); 1683 listen_port = packet_get_int(); 1684 originator_address = packet_get_string(NULL); 1685 originator_port = packet_get_int(); 1686 packet_check_eom(); 1687 1688 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d", 1689 listen_address, listen_port, originator_address, originator_port); 1690 1691 sock = channel_connect_by_listen_address(listen_port); 1692 if (sock < 0) { 1693 xfree(originator_address); 1694 xfree(listen_address); 1695 return NULL; 1696 } 1697 c = channel_new("forwarded-tcpip", 1698 SSH_CHANNEL_CONNECTING, sock, sock, -1, 1699 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1700 originator_address, 1); 1701 xfree(originator_address); 1702 xfree(listen_address); 1703 return c; 1704 } 1705 1706 static Channel * 1707 client_request_x11(const char *request_type, int rchan) 1708 { 1709 Channel *c = NULL; 1710 char *originator; 1711 int originator_port; 1712 int sock; 1713 1714 if (!options.forward_x11) { 1715 error("Warning: ssh server tried X11 forwarding."); 1716 error("Warning: this is probably a break-in attempt by a malicious server."); 1717 return NULL; 1718 } 1719 originator = packet_get_string(NULL); 1720 if (datafellows & SSH_BUG_X11FWD) { 1721 debug2("buggy server: x11 request w/o originator_port"); 1722 originator_port = 0; 1723 } else { 1724 originator_port = packet_get_int(); 1725 } 1726 packet_check_eom(); 1727 /* XXX check permission */ 1728 debug("client_request_x11: request from %s %d", originator, 1729 originator_port); 1730 xfree(originator); 1731 sock = x11_connect_display(); 1732 if (sock < 0) 1733 return NULL; 1734 c = channel_new("x11", 1735 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1736 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1737 c->force_drain = 1; 1738 return c; 1739 } 1740 1741 static Channel * 1742 client_request_agent(const char *request_type, int rchan) 1743 { 1744 Channel *c = NULL; 1745 int sock; 1746 1747 if (!options.forward_agent) { 1748 error("Warning: ssh server tried agent forwarding."); 1749 error("Warning: this is probably a break-in attempt by a malicious server."); 1750 return NULL; 1751 } 1752 sock = ssh_get_authentication_socket(); 1753 if (sock < 0) 1754 return NULL; 1755 c = channel_new("authentication agent connection", 1756 SSH_CHANNEL_OPEN, sock, sock, -1, 1757 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1758 "authentication agent connection", 1); 1759 c->force_drain = 1; 1760 return c; 1761 } 1762 1763 /* XXXX move to generic input handler */ 1764 static void 1765 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1766 { 1767 Channel *c = NULL; 1768 char *ctype; 1769 int rchan; 1770 u_int rmaxpack, rwindow, len; 1771 1772 ctype = packet_get_string(&len); 1773 rchan = packet_get_int(); 1774 rwindow = packet_get_int(); 1775 rmaxpack = packet_get_int(); 1776 1777 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1778 ctype, rchan, rwindow, rmaxpack); 1779 1780 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1781 c = client_request_forwarded_tcpip(ctype, rchan); 1782 } else if (strcmp(ctype, "x11") == 0) { 1783 c = client_request_x11(ctype, rchan); 1784 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1785 c = client_request_agent(ctype, rchan); 1786 } 1787 /* XXX duplicate : */ 1788 if (c != NULL) { 1789 debug("confirm %s", ctype); 1790 c->remote_id = rchan; 1791 c->remote_window = rwindow; 1792 c->remote_maxpacket = rmaxpack; 1793 if (c->type != SSH_CHANNEL_CONNECTING) { 1794 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1795 packet_put_int(c->remote_id); 1796 packet_put_int(c->self); 1797 packet_put_int(c->local_window); 1798 packet_put_int(c->local_maxpacket); 1799 packet_send(); 1800 } 1801 } else { 1802 debug("failure %s", ctype); 1803 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1804 packet_put_int(rchan); 1805 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1806 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1807 packet_put_cstring("open failed"); 1808 packet_put_cstring(""); 1809 } 1810 packet_send(); 1811 } 1812 xfree(ctype); 1813 } 1814 static void 1815 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1816 { 1817 Channel *c = NULL; 1818 int exitval, id, reply, success = 0; 1819 char *rtype; 1820 1821 id = packet_get_int(); 1822 rtype = packet_get_string(NULL); 1823 reply = packet_get_char(); 1824 1825 debug("client_input_channel_req: channel %d rtype %s reply %d", 1826 id, rtype, reply); 1827 1828 if (id == -1) { 1829 error("client_input_channel_req: request for channel -1"); 1830 } else if ((c = channel_lookup(id)) == NULL) { 1831 error("client_input_channel_req: channel %d: unknown channel", id); 1832 } else if (strcmp(rtype, "exit-status") == 0) { 1833 exitval = packet_get_int(); 1834 if (id == session_ident) { 1835 success = 1; 1836 exit_status = exitval; 1837 } else if (c->ctl_fd == -1) { 1838 error("client_input_channel_req: unexpected channel %d", 1839 session_ident); 1840 } else { 1841 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1842 success = 1; 1843 } 1844 packet_check_eom(); 1845 } 1846 if (reply) { 1847 packet_start(success ? 1848 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1849 packet_put_int(id); 1850 packet_send(); 1851 } 1852 xfree(rtype); 1853 } 1854 static void 1855 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1856 { 1857 char *rtype; 1858 int want_reply; 1859 int success = 0; 1860 1861 rtype = packet_get_string(NULL); 1862 want_reply = packet_get_char(); 1863 debug("client_input_global_request: rtype %s want_reply %d", 1864 rtype, want_reply); 1865 if (want_reply) { 1866 packet_start(success ? 1867 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1868 packet_send(); 1869 packet_write_wait(); 1870 } 1871 xfree(rtype); 1872 } 1873 1874 void 1875 client_session2_setup(int id, int want_tty, int want_subsystem, 1876 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env, 1877 dispatch_fn *subsys_repl) 1878 { 1879 int len; 1880 Channel *c = NULL; 1881 1882 debug2("%s: id %d", __func__, id); 1883 1884 if ((c = channel_lookup(id)) == NULL) 1885 fatal("client_session2_setup: channel %d: unknown channel", id); 1886 1887 if (want_tty) { 1888 struct winsize ws; 1889 struct termios tio; 1890 1891 /* Store window size in the packet. */ 1892 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1893 memset(&ws, 0, sizeof(ws)); 1894 1895 channel_request_start(id, "pty-req", 0); 1896 packet_put_cstring(term != NULL ? term : ""); 1897 packet_put_int((u_int)ws.ws_col); 1898 packet_put_int((u_int)ws.ws_row); 1899 packet_put_int((u_int)ws.ws_xpixel); 1900 packet_put_int((u_int)ws.ws_ypixel); 1901 tio = get_saved_tio(); 1902 tty_make_modes(-1, tiop != NULL ? tiop : &tio); 1903 packet_send(); 1904 /* XXX wait for reply */ 1905 c->client_tty = 1; 1906 } 1907 1908 /* Transfer any environment variables from client to server */ 1909 if (options.num_send_env != 0 && env != NULL) { 1910 int i, j, matched; 1911 char *name, *val; 1912 1913 debug("Sending environment."); 1914 for (i = 0; env[i] != NULL; i++) { 1915 /* Split */ 1916 name = xstrdup(env[i]); 1917 if ((val = strchr(name, '=')) == NULL) { 1918 xfree(name); 1919 continue; 1920 } 1921 *val++ = '\0'; 1922 1923 matched = 0; 1924 for (j = 0; j < options.num_send_env; j++) { 1925 if (match_pattern(name, options.send_env[j])) { 1926 matched = 1; 1927 break; 1928 } 1929 } 1930 if (!matched) { 1931 debug3("Ignored env %s", name); 1932 xfree(name); 1933 continue; 1934 } 1935 1936 debug("Sending env %s = %s", name, val); 1937 channel_request_start(id, "env", 0); 1938 packet_put_cstring(name); 1939 packet_put_cstring(val); 1940 packet_send(); 1941 xfree(name); 1942 } 1943 } 1944 1945 len = buffer_len(cmd); 1946 if (len > 0) { 1947 if (len > 900) 1948 len = 900; 1949 if (want_subsystem) { 1950 debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd)); 1951 channel_request_start(id, "subsystem", subsys_repl != NULL); 1952 if (subsys_repl != NULL) { 1953 /* register callback for reply */ 1954 /* XXX we assume that client_loop has already been called */ 1955 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl); 1956 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl); 1957 } 1958 } else { 1959 debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd)); 1960 channel_request_start(id, "exec", 0); 1961 } 1962 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1963 packet_send(); 1964 } else { 1965 channel_request_start(id, "shell", 0); 1966 packet_send(); 1967 } 1968 } 1969 1970 static void 1971 client_init_dispatch_20(void) 1972 { 1973 dispatch_init(&dispatch_protocol_error); 1974 1975 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1976 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1977 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1978 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1979 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1980 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1981 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1982 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1983 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1984 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1985 1986 /* rekeying */ 1987 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1988 1989 /* global request reply messages */ 1990 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 1991 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 1992 } 1993 static void 1994 client_init_dispatch_13(void) 1995 { 1996 dispatch_init(NULL); 1997 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 1998 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 1999 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2000 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2001 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2002 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2003 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2004 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2005 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2006 2007 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2008 &client_input_agent_open : &deny_input_open); 2009 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2010 &x11_input_open : &deny_input_open); 2011 } 2012 static void 2013 client_init_dispatch_15(void) 2014 { 2015 client_init_dispatch_13(); 2016 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2017 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2018 } 2019 static void 2020 client_init_dispatch(void) 2021 { 2022 if (compat20) 2023 client_init_dispatch_20(); 2024 else if (compat13) 2025 client_init_dispatch_13(); 2026 else 2027 client_init_dispatch_15(); 2028 } 2029 2030 /* client specific fatal cleanup */ 2031 void 2032 cleanup_exit(int i) 2033 { 2034 leave_raw_mode(); 2035 leave_non_blocking(); 2036 if (options.control_path != NULL && control_fd != -1) 2037 unlink(options.control_path); 2038 _exit(i); 2039 } 2040