1 /* $OpenBSD: clientloop.c,v 1.179 2007/03/20 03:56:12 tedu 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, window, packetmax; 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 window = CHAN_SES_WINDOW_DEFAULT; 896 packetmax = CHAN_SES_PACKET_DEFAULT; 897 if (cctx->want_tty) { 898 window >>= 1; 899 packetmax >>= 1; 900 } 901 902 c = channel_new("session", SSH_CHANNEL_OPENING, 903 new_fd[0], new_fd[1], new_fd[2], window, packetmax, 904 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 905 906 /* XXX */ 907 c->ctl_fd = client_fd; 908 909 debug3("%s: channel_new: %d", __func__, c->self); 910 911 channel_send_open(c->self); 912 channel_register_confirm(c->self, client_extra_session2_setup, cctx); 913 } 914 915 static void 916 process_cmdline(void) 917 { 918 void (*handler)(int); 919 char *s, *cmd, *cancel_host; 920 int delete = 0; 921 int local = 0; 922 u_short cancel_port; 923 Forward fwd; 924 925 leave_raw_mode(); 926 handler = signal(SIGINT, SIG_IGN); 927 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 928 if (s == NULL) 929 goto out; 930 while (isspace(*s)) 931 s++; 932 if (*s == '-') 933 s++; /* Skip cmdline '-', if any */ 934 if (*s == '\0') 935 goto out; 936 937 if (*s == 'h' || *s == 'H' || *s == '?') { 938 logit("Commands:"); 939 logit(" -L[bind_address:]port:host:hostport " 940 "Request local forward"); 941 logit(" -R[bind_address:]port:host:hostport " 942 "Request remote forward"); 943 logit(" -KR[bind_address:]port " 944 "Cancel remote forward"); 945 if (!options.permit_local_command) 946 goto out; 947 logit(" !args " 948 "Execute local command"); 949 goto out; 950 } 951 952 if (*s == '!' && options.permit_local_command) { 953 s++; 954 ssh_local_cmd(s); 955 goto out; 956 } 957 958 if (*s == 'K') { 959 delete = 1; 960 s++; 961 } 962 if (*s != 'L' && *s != 'R') { 963 logit("Invalid command."); 964 goto out; 965 } 966 if (*s == 'L') 967 local = 1; 968 if (local && delete) { 969 logit("Not supported."); 970 goto out; 971 } 972 if ((!local || delete) && !compat20) { 973 logit("Not supported for SSH protocol version 1."); 974 goto out; 975 } 976 977 while (isspace(*++s)) 978 ; 979 980 if (delete) { 981 cancel_port = 0; 982 cancel_host = hpdelim(&s); /* may be NULL */ 983 if (s != NULL) { 984 cancel_port = a2port(s); 985 cancel_host = cleanhostname(cancel_host); 986 } else { 987 cancel_port = a2port(cancel_host); 988 cancel_host = NULL; 989 } 990 if (cancel_port == 0) { 991 logit("Bad forwarding close port"); 992 goto out; 993 } 994 channel_request_rforward_cancel(cancel_host, cancel_port); 995 } else { 996 if (!parse_forward(&fwd, s)) { 997 logit("Bad forwarding specification."); 998 goto out; 999 } 1000 if (local) { 1001 if (channel_setup_local_fwd_listener(fwd.listen_host, 1002 fwd.listen_port, fwd.connect_host, 1003 fwd.connect_port, options.gateway_ports) < 0) { 1004 logit("Port forwarding failed."); 1005 goto out; 1006 } 1007 } else { 1008 if (channel_request_remote_forwarding(fwd.listen_host, 1009 fwd.listen_port, fwd.connect_host, 1010 fwd.connect_port) < 0) { 1011 logit("Port forwarding failed."); 1012 goto out; 1013 } 1014 } 1015 1016 logit("Forwarding port."); 1017 } 1018 1019 out: 1020 signal(SIGINT, handler); 1021 enter_raw_mode(); 1022 if (cmd) 1023 xfree(cmd); 1024 } 1025 1026 /* process the characters one by one */ 1027 static int 1028 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) 1029 { 1030 char string[1024]; 1031 pid_t pid; 1032 int bytes = 0; 1033 u_int i; 1034 u_char ch; 1035 char *s; 1036 1037 if (len <= 0) 1038 return (0); 1039 1040 for (i = 0; i < (u_int)len; i++) { 1041 /* Get one character at a time. */ 1042 ch = buf[i]; 1043 1044 if (escape_pending) { 1045 /* We have previously seen an escape character. */ 1046 /* Clear the flag now. */ 1047 escape_pending = 0; 1048 1049 /* Process the escaped character. */ 1050 switch (ch) { 1051 case '.': 1052 /* Terminate the connection. */ 1053 snprintf(string, sizeof string, "%c.\r\n", escape_char); 1054 buffer_append(berr, string, strlen(string)); 1055 1056 quit_pending = 1; 1057 return -1; 1058 1059 case 'Z' - 64: 1060 /* Suspend the program. */ 1061 /* Print a message to that effect to the user. */ 1062 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); 1063 buffer_append(berr, string, strlen(string)); 1064 1065 /* Restore terminal modes and suspend. */ 1066 client_suspend_self(bin, bout, berr); 1067 1068 /* We have been continued. */ 1069 continue; 1070 1071 case 'B': 1072 if (compat20) { 1073 snprintf(string, sizeof string, 1074 "%cB\r\n", escape_char); 1075 buffer_append(berr, string, 1076 strlen(string)); 1077 channel_request_start(session_ident, 1078 "break", 0); 1079 packet_put_int(1000); 1080 packet_send(); 1081 } 1082 continue; 1083 1084 case 'R': 1085 if (compat20) { 1086 if (datafellows & SSH_BUG_NOREKEY) 1087 logit("Server does not support re-keying"); 1088 else 1089 need_rekeying = 1; 1090 } 1091 continue; 1092 1093 case '&': 1094 /* 1095 * Detach the program (continue to serve connections, 1096 * but put in background and no more new connections). 1097 */ 1098 /* Restore tty modes. */ 1099 leave_raw_mode(); 1100 1101 /* Stop listening for new connections. */ 1102 channel_stop_listening(); 1103 1104 snprintf(string, sizeof string, 1105 "%c& [backgrounded]\n", escape_char); 1106 buffer_append(berr, string, strlen(string)); 1107 1108 /* Fork into background. */ 1109 pid = fork(); 1110 if (pid < 0) { 1111 error("fork: %.100s", strerror(errno)); 1112 continue; 1113 } 1114 if (pid != 0) { /* This is the parent. */ 1115 /* The parent just exits. */ 1116 exit(0); 1117 } 1118 /* The child continues serving connections. */ 1119 if (compat20) { 1120 buffer_append(bin, "\004", 1); 1121 /* fake EOF on stdin */ 1122 return -1; 1123 } else if (!stdin_eof) { 1124 /* 1125 * Sending SSH_CMSG_EOF alone does not always appear 1126 * to be enough. So we try to send an EOF character 1127 * first. 1128 */ 1129 packet_start(SSH_CMSG_STDIN_DATA); 1130 packet_put_string("\004", 1); 1131 packet_send(); 1132 /* Close stdin. */ 1133 stdin_eof = 1; 1134 if (buffer_len(bin) == 0) { 1135 packet_start(SSH_CMSG_EOF); 1136 packet_send(); 1137 } 1138 } 1139 continue; 1140 1141 case '?': 1142 snprintf(string, sizeof string, 1143 "%c?\r\n\ 1144 Supported escape sequences:\r\n\ 1145 %c. - terminate connection\r\n\ 1146 %cB - send a BREAK to the remote system\r\n\ 1147 %cC - open a command line\r\n\ 1148 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1149 %c^Z - suspend ssh\r\n\ 1150 %c# - list forwarded connections\r\n\ 1151 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1152 %c? - this message\r\n\ 1153 %c%c - send the escape character by typing it twice\r\n\ 1154 (Note that escapes are only recognized immediately after newline.)\r\n", 1155 escape_char, escape_char, escape_char, escape_char, 1156 escape_char, escape_char, escape_char, escape_char, 1157 escape_char, escape_char, escape_char); 1158 buffer_append(berr, string, strlen(string)); 1159 continue; 1160 1161 case '#': 1162 snprintf(string, sizeof string, "%c#\r\n", escape_char); 1163 buffer_append(berr, string, strlen(string)); 1164 s = channel_open_message(); 1165 buffer_append(berr, s, strlen(s)); 1166 xfree(s); 1167 continue; 1168 1169 case 'C': 1170 process_cmdline(); 1171 continue; 1172 1173 default: 1174 if (ch != escape_char) { 1175 buffer_put_char(bin, escape_char); 1176 bytes++; 1177 } 1178 /* Escaped characters fall through here */ 1179 break; 1180 } 1181 } else { 1182 /* 1183 * The previous character was not an escape char. Check if this 1184 * is an escape. 1185 */ 1186 if (last_was_cr && ch == escape_char) { 1187 /* It is. Set the flag and continue to next character. */ 1188 escape_pending = 1; 1189 continue; 1190 } 1191 } 1192 1193 /* 1194 * Normal character. Record whether it was a newline, 1195 * and append it to the buffer. 1196 */ 1197 last_was_cr = (ch == '\r' || ch == '\n'); 1198 buffer_put_char(bin, ch); 1199 bytes++; 1200 } 1201 return bytes; 1202 } 1203 1204 static void 1205 client_process_input(fd_set *readset) 1206 { 1207 int len; 1208 char buf[8192]; 1209 1210 /* Read input from stdin. */ 1211 if (FD_ISSET(fileno(stdin), readset)) { 1212 /* Read as much as possible. */ 1213 len = read(fileno(stdin), buf, sizeof(buf)); 1214 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 1215 return; /* we'll try again later */ 1216 if (len <= 0) { 1217 /* 1218 * Received EOF or error. They are treated 1219 * similarly, except that an error message is printed 1220 * if it was an error condition. 1221 */ 1222 if (len < 0) { 1223 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); 1224 buffer_append(&stderr_buffer, buf, strlen(buf)); 1225 } 1226 /* Mark that we have seen EOF. */ 1227 stdin_eof = 1; 1228 /* 1229 * Send an EOF message to the server unless there is 1230 * data in the buffer. If there is data in the 1231 * buffer, no message will be sent now. Code 1232 * elsewhere will send the EOF when the buffer 1233 * becomes empty if stdin_eof is set. 1234 */ 1235 if (buffer_len(&stdin_buffer) == 0) { 1236 packet_start(SSH_CMSG_EOF); 1237 packet_send(); 1238 } 1239 } else if (escape_char == SSH_ESCAPECHAR_NONE) { 1240 /* 1241 * Normal successful read, and no escape character. 1242 * Just append the data to buffer. 1243 */ 1244 buffer_append(&stdin_buffer, buf, len); 1245 } else { 1246 /* 1247 * Normal, successful read. But we have an escape character 1248 * and have to process the characters one by one. 1249 */ 1250 if (process_escapes(&stdin_buffer, &stdout_buffer, 1251 &stderr_buffer, buf, len) == -1) 1252 return; 1253 } 1254 } 1255 } 1256 1257 static void 1258 client_process_output(fd_set *writeset) 1259 { 1260 int len; 1261 char buf[100]; 1262 1263 /* Write buffered output to stdout. */ 1264 if (FD_ISSET(fileno(stdout), writeset)) { 1265 /* Write as much data as possible. */ 1266 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1267 buffer_len(&stdout_buffer)); 1268 if (len <= 0) { 1269 if (errno == EINTR || errno == EAGAIN) 1270 len = 0; 1271 else { 1272 /* 1273 * An error or EOF was encountered. Put an 1274 * error message to stderr buffer. 1275 */ 1276 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); 1277 buffer_append(&stderr_buffer, buf, strlen(buf)); 1278 quit_pending = 1; 1279 return; 1280 } 1281 } 1282 /* Consume printed data from the buffer. */ 1283 buffer_consume(&stdout_buffer, len); 1284 stdout_bytes += len; 1285 } 1286 /* Write buffered output to stderr. */ 1287 if (FD_ISSET(fileno(stderr), writeset)) { 1288 /* Write as much data as possible. */ 1289 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1290 buffer_len(&stderr_buffer)); 1291 if (len <= 0) { 1292 if (errno == EINTR || errno == EAGAIN) 1293 len = 0; 1294 else { 1295 /* EOF or error, but can't even print error message. */ 1296 quit_pending = 1; 1297 return; 1298 } 1299 } 1300 /* Consume printed characters from the buffer. */ 1301 buffer_consume(&stderr_buffer, len); 1302 stderr_bytes += len; 1303 } 1304 } 1305 1306 /* 1307 * Get packets from the connection input buffer, and process them as long as 1308 * there are packets available. 1309 * 1310 * Any unknown packets received during the actual 1311 * session cause the session to terminate. This is 1312 * intended to make debugging easier since no 1313 * confirmations are sent. Any compatible protocol 1314 * extensions must be negotiated during the 1315 * preparatory phase. 1316 */ 1317 1318 static void 1319 client_process_buffered_input_packets(void) 1320 { 1321 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL); 1322 } 1323 1324 /* scan buf[] for '~' before sending data to the peer */ 1325 1326 static int 1327 simple_escape_filter(Channel *c, char *buf, int len) 1328 { 1329 /* XXX we assume c->extended is writeable */ 1330 return process_escapes(&c->input, &c->output, &c->extended, buf, len); 1331 } 1332 1333 static void 1334 client_channel_closed(int id, void *arg) 1335 { 1336 channel_cancel_cleanup(id); 1337 session_closed = 1; 1338 leave_raw_mode(); 1339 } 1340 1341 /* 1342 * Implements the interactive session with the server. This is called after 1343 * the user has been authenticated, and a command has been started on the 1344 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1345 * used as an escape character for terminating or suspending the session. 1346 */ 1347 1348 int 1349 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1350 { 1351 fd_set *readset = NULL, *writeset = NULL; 1352 double start_time, total_time; 1353 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1354 u_int nalloc = 0; 1355 char buf[100]; 1356 1357 debug("Entering interactive session."); 1358 1359 start_time = get_current_time(); 1360 1361 /* Initialize variables. */ 1362 escape_pending = 0; 1363 last_was_cr = 1; 1364 exit_status = -1; 1365 stdin_eof = 0; 1366 buffer_high = 64 * 1024; 1367 connection_in = packet_get_connection_in(); 1368 connection_out = packet_get_connection_out(); 1369 max_fd = MAX(connection_in, connection_out); 1370 if (control_fd != -1) 1371 max_fd = MAX(max_fd, control_fd); 1372 1373 if (!compat20) { 1374 /* enable nonblocking unless tty */ 1375 if (!isatty(fileno(stdin))) 1376 set_nonblock(fileno(stdin)); 1377 if (!isatty(fileno(stdout))) 1378 set_nonblock(fileno(stdout)); 1379 if (!isatty(fileno(stderr))) 1380 set_nonblock(fileno(stderr)); 1381 max_fd = MAX(max_fd, fileno(stdin)); 1382 max_fd = MAX(max_fd, fileno(stdout)); 1383 max_fd = MAX(max_fd, fileno(stderr)); 1384 } 1385 stdin_bytes = 0; 1386 stdout_bytes = 0; 1387 stderr_bytes = 0; 1388 quit_pending = 0; 1389 escape_char = escape_char_arg; 1390 1391 /* Initialize buffers. */ 1392 buffer_init(&stdin_buffer); 1393 buffer_init(&stdout_buffer); 1394 buffer_init(&stderr_buffer); 1395 1396 client_init_dispatch(); 1397 1398 /* 1399 * Set signal handlers, (e.g. to restore non-blocking mode) 1400 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1401 */ 1402 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1403 signal(SIGHUP, signal_handler); 1404 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1405 signal(SIGINT, signal_handler); 1406 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1407 signal(SIGQUIT, signal_handler); 1408 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1409 signal(SIGTERM, signal_handler); 1410 signal(SIGWINCH, window_change_handler); 1411 1412 if (have_pty) 1413 enter_raw_mode(); 1414 1415 if (compat20) { 1416 session_ident = ssh2_chan_id; 1417 if (escape_char != SSH_ESCAPECHAR_NONE) 1418 channel_register_filter(session_ident, 1419 simple_escape_filter, NULL); 1420 if (session_ident != -1) 1421 channel_register_cleanup(session_ident, 1422 client_channel_closed, 0); 1423 } else { 1424 /* Check if we should immediately send eof on stdin. */ 1425 client_check_initial_eof_on_stdin(); 1426 } 1427 1428 /* Main loop of the client for the interactive session mode. */ 1429 while (!quit_pending) { 1430 1431 /* Process buffered packets sent by the server. */ 1432 client_process_buffered_input_packets(); 1433 1434 if (compat20 && session_closed && !channel_still_open()) 1435 break; 1436 1437 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1438 1439 if (rekeying) { 1440 debug("rekeying in progress"); 1441 } else { 1442 /* 1443 * Make packets of buffered stdin data, and buffer 1444 * them for sending to the server. 1445 */ 1446 if (!compat20) 1447 client_make_packets_from_stdin_data(); 1448 1449 /* 1450 * Make packets from buffered channel data, and 1451 * enqueue them for sending to the server. 1452 */ 1453 if (packet_not_very_much_data_to_write()) 1454 channel_output_poll(); 1455 1456 /* 1457 * Check if the window size has changed, and buffer a 1458 * message about it to the server if so. 1459 */ 1460 client_check_window_change(); 1461 1462 if (quit_pending) 1463 break; 1464 } 1465 /* 1466 * Wait until we have something to do (something becomes 1467 * available on one of the descriptors). 1468 */ 1469 max_fd2 = max_fd; 1470 client_wait_until_can_do_something(&readset, &writeset, 1471 &max_fd2, &nalloc, rekeying); 1472 1473 if (quit_pending) 1474 break; 1475 1476 /* Do channel operations unless rekeying in progress. */ 1477 if (!rekeying) { 1478 channel_after_select(readset, writeset); 1479 if (need_rekeying || packet_need_rekeying()) { 1480 debug("need rekeying"); 1481 xxx_kex->done = 0; 1482 kex_send_kexinit(xxx_kex); 1483 need_rekeying = 0; 1484 } 1485 } 1486 1487 /* Buffer input from the connection. */ 1488 client_process_net_input(readset); 1489 1490 /* Accept control connections. */ 1491 client_process_control(readset); 1492 1493 if (quit_pending) 1494 break; 1495 1496 if (!compat20) { 1497 /* Buffer data from stdin */ 1498 client_process_input(readset); 1499 /* 1500 * Process output to stdout and stderr. Output to 1501 * the connection is processed elsewhere (above). 1502 */ 1503 client_process_output(writeset); 1504 } 1505 1506 /* Send as much buffered packet data as possible to the sender. */ 1507 if (FD_ISSET(connection_out, writeset)) 1508 packet_write_poll(); 1509 } 1510 if (readset) 1511 xfree(readset); 1512 if (writeset) 1513 xfree(writeset); 1514 1515 /* Terminate the session. */ 1516 1517 /* Stop watching for window change. */ 1518 signal(SIGWINCH, SIG_DFL); 1519 1520 channel_free_all(); 1521 1522 if (have_pty) 1523 leave_raw_mode(); 1524 1525 /* restore blocking io */ 1526 if (!isatty(fileno(stdin))) 1527 unset_nonblock(fileno(stdin)); 1528 if (!isatty(fileno(stdout))) 1529 unset_nonblock(fileno(stdout)); 1530 if (!isatty(fileno(stderr))) 1531 unset_nonblock(fileno(stderr)); 1532 1533 /* 1534 * If there was no shell or command requested, there will be no remote 1535 * exit status to be returned. In that case, clear error code if the 1536 * connection was deliberately terminated at this end. 1537 */ 1538 if (no_shell_flag && received_signal == SIGTERM) { 1539 received_signal = 0; 1540 exit_status = 0; 1541 } 1542 1543 if (received_signal) 1544 fatal("Killed by signal %d.", (int) received_signal); 1545 1546 /* 1547 * In interactive mode (with pseudo tty) display a message indicating 1548 * that the connection has been closed. 1549 */ 1550 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1551 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); 1552 buffer_append(&stderr_buffer, buf, strlen(buf)); 1553 } 1554 1555 /* Output any buffered data for stdout. */ 1556 while (buffer_len(&stdout_buffer) > 0) { 1557 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1558 buffer_len(&stdout_buffer)); 1559 if (len <= 0) { 1560 error("Write failed flushing stdout buffer."); 1561 break; 1562 } 1563 buffer_consume(&stdout_buffer, len); 1564 stdout_bytes += len; 1565 } 1566 1567 /* Output any buffered data for stderr. */ 1568 while (buffer_len(&stderr_buffer) > 0) { 1569 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1570 buffer_len(&stderr_buffer)); 1571 if (len <= 0) { 1572 error("Write failed flushing stderr buffer."); 1573 break; 1574 } 1575 buffer_consume(&stderr_buffer, len); 1576 stderr_bytes += len; 1577 } 1578 1579 /* Clear and free any buffers. */ 1580 memset(buf, 0, sizeof(buf)); 1581 buffer_free(&stdin_buffer); 1582 buffer_free(&stdout_buffer); 1583 buffer_free(&stderr_buffer); 1584 1585 /* Report bytes transferred, and transfer rates. */ 1586 total_time = get_current_time() - start_time; 1587 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", 1588 stdin_bytes, stdout_bytes, stderr_bytes, total_time); 1589 if (total_time > 0) 1590 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", 1591 stdin_bytes / total_time, stdout_bytes / total_time, 1592 stderr_bytes / total_time); 1593 1594 /* Return the exit status of the program. */ 1595 debug("Exit status %d", exit_status); 1596 return exit_status; 1597 } 1598 1599 /*********/ 1600 1601 static void 1602 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1603 { 1604 u_int data_len; 1605 char *data = packet_get_string(&data_len); 1606 packet_check_eom(); 1607 buffer_append(&stdout_buffer, data, data_len); 1608 memset(data, 0, data_len); 1609 xfree(data); 1610 } 1611 static void 1612 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1613 { 1614 u_int data_len; 1615 char *data = packet_get_string(&data_len); 1616 packet_check_eom(); 1617 buffer_append(&stderr_buffer, data, data_len); 1618 memset(data, 0, data_len); 1619 xfree(data); 1620 } 1621 static void 1622 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1623 { 1624 exit_status = packet_get_int(); 1625 packet_check_eom(); 1626 /* Acknowledge the exit. */ 1627 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1628 packet_send(); 1629 /* 1630 * Must wait for packet to be sent since we are 1631 * exiting the loop. 1632 */ 1633 packet_write_wait(); 1634 /* Flag that we want to exit. */ 1635 quit_pending = 1; 1636 } 1637 static void 1638 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1639 { 1640 Channel *c = NULL; 1641 int remote_id, sock; 1642 1643 /* Read the remote channel number from the message. */ 1644 remote_id = packet_get_int(); 1645 packet_check_eom(); 1646 1647 /* 1648 * Get a connection to the local authentication agent (this may again 1649 * get forwarded). 1650 */ 1651 sock = ssh_get_authentication_socket(); 1652 1653 /* 1654 * If we could not connect the agent, send an error message back to 1655 * the server. This should never happen unless the agent dies, 1656 * because authentication forwarding is only enabled if we have an 1657 * agent. 1658 */ 1659 if (sock >= 0) { 1660 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1661 -1, 0, 0, 0, "authentication agent connection", 1); 1662 c->remote_id = remote_id; 1663 c->force_drain = 1; 1664 } 1665 if (c == NULL) { 1666 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1667 packet_put_int(remote_id); 1668 } else { 1669 /* Send a confirmation to the remote host. */ 1670 debug("Forwarding authentication connection."); 1671 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1672 packet_put_int(remote_id); 1673 packet_put_int(c->self); 1674 } 1675 packet_send(); 1676 } 1677 1678 static Channel * 1679 client_request_forwarded_tcpip(const char *request_type, int rchan) 1680 { 1681 Channel *c = NULL; 1682 char *listen_address, *originator_address; 1683 int listen_port, originator_port; 1684 int sock; 1685 1686 /* Get rest of the packet */ 1687 listen_address = packet_get_string(NULL); 1688 listen_port = packet_get_int(); 1689 originator_address = packet_get_string(NULL); 1690 originator_port = packet_get_int(); 1691 packet_check_eom(); 1692 1693 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d", 1694 listen_address, listen_port, originator_address, originator_port); 1695 1696 sock = channel_connect_by_listen_address(listen_port); 1697 if (sock < 0) { 1698 xfree(originator_address); 1699 xfree(listen_address); 1700 return NULL; 1701 } 1702 c = channel_new("forwarded-tcpip", 1703 SSH_CHANNEL_CONNECTING, sock, sock, -1, 1704 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1705 originator_address, 1); 1706 xfree(originator_address); 1707 xfree(listen_address); 1708 return c; 1709 } 1710 1711 static Channel * 1712 client_request_x11(const char *request_type, int rchan) 1713 { 1714 Channel *c = NULL; 1715 char *originator; 1716 int originator_port; 1717 int sock; 1718 1719 if (!options.forward_x11) { 1720 error("Warning: ssh server tried X11 forwarding."); 1721 error("Warning: this is probably a break-in attempt by a malicious server."); 1722 return NULL; 1723 } 1724 originator = packet_get_string(NULL); 1725 if (datafellows & SSH_BUG_X11FWD) { 1726 debug2("buggy server: x11 request w/o originator_port"); 1727 originator_port = 0; 1728 } else { 1729 originator_port = packet_get_int(); 1730 } 1731 packet_check_eom(); 1732 /* XXX check permission */ 1733 debug("client_request_x11: request from %s %d", originator, 1734 originator_port); 1735 xfree(originator); 1736 sock = x11_connect_display(); 1737 if (sock < 0) 1738 return NULL; 1739 c = channel_new("x11", 1740 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1741 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1742 c->force_drain = 1; 1743 return c; 1744 } 1745 1746 static Channel * 1747 client_request_agent(const char *request_type, int rchan) 1748 { 1749 Channel *c = NULL; 1750 int sock; 1751 1752 if (!options.forward_agent) { 1753 error("Warning: ssh server tried agent forwarding."); 1754 error("Warning: this is probably a break-in attempt by a malicious server."); 1755 return NULL; 1756 } 1757 sock = ssh_get_authentication_socket(); 1758 if (sock < 0) 1759 return NULL; 1760 c = channel_new("authentication agent connection", 1761 SSH_CHANNEL_OPEN, sock, sock, -1, 1762 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1763 "authentication agent connection", 1); 1764 c->force_drain = 1; 1765 return c; 1766 } 1767 1768 /* XXXX move to generic input handler */ 1769 static void 1770 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1771 { 1772 Channel *c = NULL; 1773 char *ctype; 1774 int rchan; 1775 u_int rmaxpack, rwindow, len; 1776 1777 ctype = packet_get_string(&len); 1778 rchan = packet_get_int(); 1779 rwindow = packet_get_int(); 1780 rmaxpack = packet_get_int(); 1781 1782 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1783 ctype, rchan, rwindow, rmaxpack); 1784 1785 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1786 c = client_request_forwarded_tcpip(ctype, rchan); 1787 } else if (strcmp(ctype, "x11") == 0) { 1788 c = client_request_x11(ctype, rchan); 1789 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1790 c = client_request_agent(ctype, rchan); 1791 } 1792 /* XXX duplicate : */ 1793 if (c != NULL) { 1794 debug("confirm %s", ctype); 1795 c->remote_id = rchan; 1796 c->remote_window = rwindow; 1797 c->remote_maxpacket = rmaxpack; 1798 if (c->type != SSH_CHANNEL_CONNECTING) { 1799 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1800 packet_put_int(c->remote_id); 1801 packet_put_int(c->self); 1802 packet_put_int(c->local_window); 1803 packet_put_int(c->local_maxpacket); 1804 packet_send(); 1805 } 1806 } else { 1807 debug("failure %s", ctype); 1808 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1809 packet_put_int(rchan); 1810 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1811 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1812 packet_put_cstring("open failed"); 1813 packet_put_cstring(""); 1814 } 1815 packet_send(); 1816 } 1817 xfree(ctype); 1818 } 1819 static void 1820 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1821 { 1822 Channel *c = NULL; 1823 int exitval, id, reply, success = 0; 1824 char *rtype; 1825 1826 id = packet_get_int(); 1827 rtype = packet_get_string(NULL); 1828 reply = packet_get_char(); 1829 1830 debug("client_input_channel_req: channel %d rtype %s reply %d", 1831 id, rtype, reply); 1832 1833 if (id == -1) { 1834 error("client_input_channel_req: request for channel -1"); 1835 } else if ((c = channel_lookup(id)) == NULL) { 1836 error("client_input_channel_req: channel %d: unknown channel", id); 1837 } else if (strcmp(rtype, "exit-status") == 0) { 1838 exitval = packet_get_int(); 1839 if (id == session_ident) { 1840 success = 1; 1841 exit_status = exitval; 1842 } else if (c->ctl_fd == -1) { 1843 error("client_input_channel_req: unexpected channel %d", 1844 session_ident); 1845 } else { 1846 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1847 success = 1; 1848 } 1849 packet_check_eom(); 1850 } 1851 if (reply) { 1852 packet_start(success ? 1853 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1854 packet_put_int(id); 1855 packet_send(); 1856 } 1857 xfree(rtype); 1858 } 1859 static void 1860 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1861 { 1862 char *rtype; 1863 int want_reply; 1864 int success = 0; 1865 1866 rtype = packet_get_string(NULL); 1867 want_reply = packet_get_char(); 1868 debug("client_input_global_request: rtype %s want_reply %d", 1869 rtype, want_reply); 1870 if (want_reply) { 1871 packet_start(success ? 1872 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1873 packet_send(); 1874 packet_write_wait(); 1875 } 1876 xfree(rtype); 1877 } 1878 1879 void 1880 client_session2_setup(int id, int want_tty, int want_subsystem, 1881 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env, 1882 dispatch_fn *subsys_repl) 1883 { 1884 int len; 1885 Channel *c = NULL; 1886 1887 debug2("%s: id %d", __func__, id); 1888 1889 if ((c = channel_lookup(id)) == NULL) 1890 fatal("client_session2_setup: channel %d: unknown channel", id); 1891 1892 if (want_tty) { 1893 struct winsize ws; 1894 struct termios tio; 1895 1896 /* Store window size in the packet. */ 1897 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1898 memset(&ws, 0, sizeof(ws)); 1899 1900 channel_request_start(id, "pty-req", 0); 1901 packet_put_cstring(term != NULL ? term : ""); 1902 packet_put_int((u_int)ws.ws_col); 1903 packet_put_int((u_int)ws.ws_row); 1904 packet_put_int((u_int)ws.ws_xpixel); 1905 packet_put_int((u_int)ws.ws_ypixel); 1906 tio = get_saved_tio(); 1907 tty_make_modes(-1, tiop != NULL ? tiop : &tio); 1908 packet_send(); 1909 /* XXX wait for reply */ 1910 c->client_tty = 1; 1911 } 1912 1913 /* Transfer any environment variables from client to server */ 1914 if (options.num_send_env != 0 && env != NULL) { 1915 int i, j, matched; 1916 char *name, *val; 1917 1918 debug("Sending environment."); 1919 for (i = 0; env[i] != NULL; i++) { 1920 /* Split */ 1921 name = xstrdup(env[i]); 1922 if ((val = strchr(name, '=')) == NULL) { 1923 xfree(name); 1924 continue; 1925 } 1926 *val++ = '\0'; 1927 1928 matched = 0; 1929 for (j = 0; j < options.num_send_env; j++) { 1930 if (match_pattern(name, options.send_env[j])) { 1931 matched = 1; 1932 break; 1933 } 1934 } 1935 if (!matched) { 1936 debug3("Ignored env %s", name); 1937 xfree(name); 1938 continue; 1939 } 1940 1941 debug("Sending env %s = %s", name, val); 1942 channel_request_start(id, "env", 0); 1943 packet_put_cstring(name); 1944 packet_put_cstring(val); 1945 packet_send(); 1946 xfree(name); 1947 } 1948 } 1949 1950 len = buffer_len(cmd); 1951 if (len > 0) { 1952 if (len > 900) 1953 len = 900; 1954 if (want_subsystem) { 1955 debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd)); 1956 channel_request_start(id, "subsystem", subsys_repl != NULL); 1957 if (subsys_repl != NULL) { 1958 /* register callback for reply */ 1959 /* XXX we assume that client_loop has already been called */ 1960 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl); 1961 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl); 1962 } 1963 } else { 1964 debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd)); 1965 channel_request_start(id, "exec", 0); 1966 } 1967 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1968 packet_send(); 1969 } else { 1970 channel_request_start(id, "shell", 0); 1971 packet_send(); 1972 } 1973 } 1974 1975 static void 1976 client_init_dispatch_20(void) 1977 { 1978 dispatch_init(&dispatch_protocol_error); 1979 1980 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1981 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1982 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1983 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1984 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1985 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1986 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1987 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1988 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1989 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1990 1991 /* rekeying */ 1992 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1993 1994 /* global request reply messages */ 1995 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 1996 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 1997 } 1998 static void 1999 client_init_dispatch_13(void) 2000 { 2001 dispatch_init(NULL); 2002 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 2003 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 2004 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2005 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2006 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2007 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2008 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2009 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2010 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2011 2012 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2013 &client_input_agent_open : &deny_input_open); 2014 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2015 &x11_input_open : &deny_input_open); 2016 } 2017 static void 2018 client_init_dispatch_15(void) 2019 { 2020 client_init_dispatch_13(); 2021 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2022 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2023 } 2024 static void 2025 client_init_dispatch(void) 2026 { 2027 if (compat20) 2028 client_init_dispatch_20(); 2029 else if (compat13) 2030 client_init_dispatch_13(); 2031 else 2032 client_init_dispatch_15(); 2033 } 2034 2035 /* client specific fatal cleanup */ 2036 void 2037 cleanup_exit(int i) 2038 { 2039 leave_raw_mode(); 2040 leave_non_blocking(); 2041 if (options.control_path != NULL && control_fd != -1) 2042 unlink(options.control_path); 2043 _exit(i); 2044 } 2045