1 /* 2 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * The main loop for the interactive session (client side). 6 * 7 * As far as I am concerned, the code I have written for this software 8 * can be used freely for any purpose. Any derived versions of this 9 * software must be clearly marked as such, and if the derived work is 10 * incompatible with the protocol description in the RFC file, it must be 11 * called by a name other than "ssh" or "Secure Shell". 12 * 13 * 14 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 * 36 * 37 * SSH2 support added by Markus Friedl. 38 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 50 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 51 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 52 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 53 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 54 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 55 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 56 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 57 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 58 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 59 */ 60 61 #include "includes.h" 62 RCSID("$OpenBSD: clientloop.c,v 1.130 2004/08/11 21:43:04 avsm Exp $"); 63 64 #include "ssh.h" 65 #include "ssh1.h" 66 #include "ssh2.h" 67 #include "xmalloc.h" 68 #include "packet.h" 69 #include "buffer.h" 70 #include "compat.h" 71 #include "channels.h" 72 #include "dispatch.h" 73 #include "buffer.h" 74 #include "bufaux.h" 75 #include "key.h" 76 #include "kex.h" 77 #include "log.h" 78 #include "readconf.h" 79 #include "clientloop.h" 80 #include "authfd.h" 81 #include "atomicio.h" 82 #include "sshpty.h" 83 #include "misc.h" 84 #include "monitor_fdpass.h" 85 #include "match.h" 86 #include "msg.h" 87 88 /* import options */ 89 extern Options options; 90 91 /* Flag indicating that stdin should be redirected from /dev/null. */ 92 extern int stdin_null_flag; 93 94 /* Flag indicating that no shell has been requested */ 95 extern int no_shell_flag; 96 97 /* Control socket */ 98 extern int control_fd; 99 100 /* 101 * Name of the host we are connecting to. This is the name given on the 102 * command line, or the HostName specified for the user-supplied name in a 103 * configuration file. 104 */ 105 extern char *host; 106 107 /* 108 * Flag to indicate that we have received a window change signal which has 109 * not yet been processed. This will cause a message indicating the new 110 * window size to be sent to the server a little later. This is volatile 111 * because this is updated in a signal handler. 112 */ 113 static volatile sig_atomic_t received_window_change_signal = 0; 114 static volatile sig_atomic_t received_signal = 0; 115 116 /* Flag indicating whether the user\'s terminal is in non-blocking mode. */ 117 static int in_non_blocking_mode = 0; 118 119 /* Common data for the client loop code. */ 120 static int quit_pending; /* Set to non-zero to quit the client loop. */ 121 static int escape_char; /* Escape character. */ 122 static int escape_pending; /* Last character was the escape character */ 123 static int last_was_cr; /* Last character was a newline. */ 124 static int exit_status; /* Used to store the exit status of the command. */ 125 static int stdin_eof; /* EOF has been encountered on standard error. */ 126 static Buffer stdin_buffer; /* Buffer for stdin data. */ 127 static Buffer stdout_buffer; /* Buffer for stdout data. */ 128 static Buffer stderr_buffer; /* Buffer for stderr data. */ 129 static u_long stdin_bytes, stdout_bytes, stderr_bytes; 130 static u_int buffer_high;/* Soft max buffer size. */ 131 static int connection_in; /* Connection to server (input). */ 132 static int connection_out; /* Connection to server (output). */ 133 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 134 static int session_closed = 0; /* In SSH2: login session closed. */ 135 static int server_alive_timeouts = 0; 136 137 static void client_init_dispatch(void); 138 int session_ident = -1; 139 140 struct confirm_ctx { 141 int want_tty; 142 int want_subsys; 143 Buffer cmd; 144 char *term; 145 struct termios tio; 146 char **env; 147 }; 148 149 /*XXX*/ 150 extern Kex *xxx_kex; 151 152 void ssh_process_session2_setup(int, int, int, Buffer *); 153 154 /* Restores stdin to blocking mode. */ 155 156 static void 157 leave_non_blocking(void) 158 { 159 if (in_non_blocking_mode) { 160 unset_nonblock(fileno(stdin)); 161 in_non_blocking_mode = 0; 162 } 163 } 164 165 /* Puts stdin terminal in non-blocking mode. */ 166 167 static void 168 enter_non_blocking(void) 169 { 170 in_non_blocking_mode = 1; 171 set_nonblock(fileno(stdin)); 172 } 173 174 /* 175 * Signal handler for the window change signal (SIGWINCH). This just sets a 176 * flag indicating that the window has changed. 177 */ 178 179 static void 180 window_change_handler(int sig) 181 { 182 received_window_change_signal = 1; 183 signal(SIGWINCH, window_change_handler); 184 } 185 186 /* 187 * Signal handler for signals that cause the program to terminate. These 188 * signals must be trapped to restore terminal modes. 189 */ 190 191 static void 192 signal_handler(int sig) 193 { 194 received_signal = sig; 195 quit_pending = 1; 196 } 197 198 /* 199 * Returns current time in seconds from Jan 1, 1970 with the maximum 200 * available resolution. 201 */ 202 203 static double 204 get_current_time(void) 205 { 206 struct timeval tv; 207 gettimeofday(&tv, NULL); 208 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 209 } 210 211 /* 212 * This is called when the interactive is entered. This checks if there is 213 * an EOF coming on stdin. We must check this explicitly, as select() does 214 * not appear to wake up when redirecting from /dev/null. 215 */ 216 217 static void 218 client_check_initial_eof_on_stdin(void) 219 { 220 int len; 221 char buf[1]; 222 223 /* 224 * If standard input is to be "redirected from /dev/null", we simply 225 * mark that we have seen an EOF and send an EOF message to the 226 * server. Otherwise, we try to read a single character; it appears 227 * that for some files, such /dev/null, select() never wakes up for 228 * read for this descriptor, which means that we never get EOF. This 229 * way we will get the EOF if stdin comes from /dev/null or similar. 230 */ 231 if (stdin_null_flag) { 232 /* Fake EOF on stdin. */ 233 debug("Sending eof."); 234 stdin_eof = 1; 235 packet_start(SSH_CMSG_EOF); 236 packet_send(); 237 } else { 238 enter_non_blocking(); 239 240 /* Check for immediate EOF on stdin. */ 241 len = read(fileno(stdin), buf, 1); 242 if (len == 0) { 243 /* EOF. Record that we have seen it and send EOF to server. */ 244 debug("Sending eof."); 245 stdin_eof = 1; 246 packet_start(SSH_CMSG_EOF); 247 packet_send(); 248 } else if (len > 0) { 249 /* 250 * Got data. We must store the data in the buffer, 251 * and also process it as an escape character if 252 * appropriate. 253 */ 254 if ((u_char) buf[0] == escape_char) 255 escape_pending = 1; 256 else 257 buffer_append(&stdin_buffer, buf, 1); 258 } 259 leave_non_blocking(); 260 } 261 } 262 263 264 /* 265 * Make packets from buffered stdin data, and buffer them for sending to the 266 * connection. 267 */ 268 269 static void 270 client_make_packets_from_stdin_data(void) 271 { 272 u_int len; 273 274 /* Send buffered stdin data to the server. */ 275 while (buffer_len(&stdin_buffer) > 0 && 276 packet_not_very_much_data_to_write()) { 277 len = buffer_len(&stdin_buffer); 278 /* Keep the packets at reasonable size. */ 279 if (len > packet_get_maxsize()) 280 len = packet_get_maxsize(); 281 packet_start(SSH_CMSG_STDIN_DATA); 282 packet_put_string(buffer_ptr(&stdin_buffer), len); 283 packet_send(); 284 buffer_consume(&stdin_buffer, len); 285 stdin_bytes += len; 286 /* If we have a pending EOF, send it now. */ 287 if (stdin_eof && buffer_len(&stdin_buffer) == 0) { 288 packet_start(SSH_CMSG_EOF); 289 packet_send(); 290 } 291 } 292 } 293 294 /* 295 * Checks if the client window has changed, and sends a packet about it to 296 * the server if so. The actual change is detected elsewhere (by a software 297 * interrupt on Unix); this just checks the flag and sends a message if 298 * appropriate. 299 */ 300 301 static void 302 client_check_window_change(void) 303 { 304 struct winsize ws; 305 306 if (! received_window_change_signal) 307 return; 308 /** XXX race */ 309 received_window_change_signal = 0; 310 311 debug2("client_check_window_change: changed"); 312 313 if (compat20) { 314 channel_send_window_changes(); 315 } else { 316 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 317 return; 318 packet_start(SSH_CMSG_WINDOW_SIZE); 319 packet_put_int(ws.ws_row); 320 packet_put_int(ws.ws_col); 321 packet_put_int(ws.ws_xpixel); 322 packet_put_int(ws.ws_ypixel); 323 packet_send(); 324 } 325 } 326 327 static void 328 client_global_request_reply(int type, u_int32_t seq, void *ctxt) 329 { 330 server_alive_timeouts = 0; 331 client_global_request_reply_fwd(type, seq, ctxt); 332 } 333 334 static void 335 server_alive_check(void) 336 { 337 if (++server_alive_timeouts > options.server_alive_count_max) 338 packet_disconnect("Timeout, server not responding."); 339 packet_start(SSH2_MSG_GLOBAL_REQUEST); 340 packet_put_cstring("keepalive@openssh.com"); 341 packet_put_char(1); /* boolean: want reply */ 342 packet_send(); 343 } 344 345 /* 346 * Waits until the client can do something (some data becomes available on 347 * one of the file descriptors). 348 */ 349 static void 350 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 351 int *maxfdp, u_int *nallocp, int rekeying) 352 { 353 struct timeval tv, *tvp; 354 int ret; 355 356 /* Add any selections by the channel mechanism. */ 357 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); 358 359 if (!compat20) { 360 /* Read from the connection, unless our buffers are full. */ 361 if (buffer_len(&stdout_buffer) < buffer_high && 362 buffer_len(&stderr_buffer) < buffer_high && 363 channel_not_very_much_buffered_data()) 364 FD_SET(connection_in, *readsetp); 365 /* 366 * Read from stdin, unless we have seen EOF or have very much 367 * buffered data to send to the server. 368 */ 369 if (!stdin_eof && packet_not_very_much_data_to_write()) 370 FD_SET(fileno(stdin), *readsetp); 371 372 /* Select stdout/stderr if have data in buffer. */ 373 if (buffer_len(&stdout_buffer) > 0) 374 FD_SET(fileno(stdout), *writesetp); 375 if (buffer_len(&stderr_buffer) > 0) 376 FD_SET(fileno(stderr), *writesetp); 377 } else { 378 /* channel_prepare_select could have closed the last channel */ 379 if (session_closed && !channel_still_open() && 380 !packet_have_data_to_write()) { 381 /* clear mask since we did not call select() */ 382 memset(*readsetp, 0, *nallocp); 383 memset(*writesetp, 0, *nallocp); 384 return; 385 } else { 386 FD_SET(connection_in, *readsetp); 387 } 388 } 389 390 /* Select server connection if have data to write to the server. */ 391 if (packet_have_data_to_write()) 392 FD_SET(connection_out, *writesetp); 393 394 if (control_fd != -1) 395 FD_SET(control_fd, *readsetp); 396 397 /* 398 * Wait for something to happen. This will suspend the process until 399 * some selected descriptor can be read, written, or has some other 400 * event pending. 401 */ 402 403 if (options.server_alive_interval == 0 || !compat20) 404 tvp = NULL; 405 else { 406 tv.tv_sec = options.server_alive_interval; 407 tv.tv_usec = 0; 408 tvp = &tv; 409 } 410 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 411 if (ret < 0) { 412 char buf[100]; 413 414 /* 415 * We have to clear the select masks, because we return. 416 * We have to return, because the mainloop checks for the flags 417 * set by the signal handlers. 418 */ 419 memset(*readsetp, 0, *nallocp); 420 memset(*writesetp, 0, *nallocp); 421 422 if (errno == EINTR) 423 return; 424 /* Note: we might still have data in the buffers. */ 425 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 426 buffer_append(&stderr_buffer, buf, strlen(buf)); 427 quit_pending = 1; 428 } else if (ret == 0) 429 server_alive_check(); 430 } 431 432 static void 433 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 434 { 435 struct winsize oldws, newws; 436 437 /* Flush stdout and stderr buffers. */ 438 if (buffer_len(bout) > 0) 439 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout)); 440 if (buffer_len(berr) > 0) 441 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr)); 442 443 leave_raw_mode(); 444 445 /* 446 * Free (and clear) the buffer to reduce the amount of data that gets 447 * written to swap. 448 */ 449 buffer_free(bin); 450 buffer_free(bout); 451 buffer_free(berr); 452 453 /* Save old window size. */ 454 ioctl(fileno(stdin), TIOCGWINSZ, &oldws); 455 456 /* Send the suspend signal to the program itself. */ 457 kill(getpid(), SIGTSTP); 458 459 /* Check if the window size has changed. */ 460 if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 && 461 (oldws.ws_row != newws.ws_row || 462 oldws.ws_col != newws.ws_col || 463 oldws.ws_xpixel != newws.ws_xpixel || 464 oldws.ws_ypixel != newws.ws_ypixel)) 465 received_window_change_signal = 1; 466 467 /* OK, we have been continued by the user. Reinitialize buffers. */ 468 buffer_init(bin); 469 buffer_init(bout); 470 buffer_init(berr); 471 472 enter_raw_mode(); 473 } 474 475 static void 476 client_process_net_input(fd_set * readset) 477 { 478 int len; 479 char buf[8192]; 480 481 /* 482 * Read input from the server, and add any such data to the buffer of 483 * the packet subsystem. 484 */ 485 if (FD_ISSET(connection_in, readset)) { 486 /* Read as much as possible. */ 487 len = read(connection_in, buf, sizeof(buf)); 488 if (len == 0) { 489 /* Received EOF. The remote host has closed the connection. */ 490 snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", 491 host); 492 buffer_append(&stderr_buffer, buf, strlen(buf)); 493 quit_pending = 1; 494 return; 495 } 496 /* 497 * There is a kernel bug on Solaris that causes select to 498 * sometimes wake up even though there is no data available. 499 */ 500 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 501 len = 0; 502 503 if (len < 0) { 504 /* An error has encountered. Perhaps there is a network problem. */ 505 snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", 506 host, strerror(errno)); 507 buffer_append(&stderr_buffer, buf, strlen(buf)); 508 quit_pending = 1; 509 return; 510 } 511 packet_process_incoming(buf, len); 512 } 513 } 514 515 static void 516 client_subsystem_reply(int type, u_int32_t seq, void *ctxt) 517 { 518 int id; 519 Channel *c; 520 521 id = packet_get_int(); 522 packet_check_eom(); 523 524 if ((c = channel_lookup(id)) == NULL) { 525 error("%s: no channel for id %d", __func__, id); 526 return; 527 } 528 529 if (type == SSH2_MSG_CHANNEL_SUCCESS) 530 debug2("Request suceeded on channel %d", id); 531 else if (type == SSH2_MSG_CHANNEL_FAILURE) { 532 error("Request failed on channel %d", id); 533 channel_free(c); 534 } 535 } 536 537 static void 538 client_extra_session2_setup(int id, void *arg) 539 { 540 struct confirm_ctx *cctx = arg; 541 Channel *c; 542 int i; 543 544 if (cctx == NULL) 545 fatal("%s: cctx == NULL", __func__); 546 if ((c = channel_lookup(id)) == NULL) 547 fatal("%s: no channel for id %d", __func__, id); 548 549 client_session2_setup(id, cctx->want_tty, cctx->want_subsys, 550 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env, 551 client_subsystem_reply); 552 553 c->confirm_ctx = NULL; 554 buffer_free(&cctx->cmd); 555 xfree(cctx->term); 556 if (cctx->env != NULL) { 557 for (i = 0; cctx->env[i] != NULL; i++) 558 xfree(cctx->env[i]); 559 xfree(cctx->env); 560 } 561 xfree(cctx); 562 } 563 564 static void 565 client_process_control(fd_set * readset) 566 { 567 Buffer m; 568 Channel *c; 569 int client_fd, new_fd[3], ver, i, allowed; 570 socklen_t addrlen; 571 struct sockaddr_storage addr; 572 struct confirm_ctx *cctx; 573 char *cmd; 574 u_int len, env_len; 575 uid_t euid; 576 gid_t egid; 577 578 /* 579 * Accept connection on control socket 580 */ 581 if (control_fd == -1 || !FD_ISSET(control_fd, readset)) 582 return; 583 584 memset(&addr, 0, sizeof(addr)); 585 addrlen = sizeof(addr); 586 if ((client_fd = accept(control_fd, 587 (struct sockaddr*)&addr, &addrlen)) == -1) { 588 error("%s accept: %s", __func__, strerror(errno)); 589 return; 590 } 591 592 if (getpeereid(client_fd, &euid, &egid) < 0) { 593 error("%s getpeereid failed: %s", __func__, strerror(errno)); 594 close(client_fd); 595 return; 596 } 597 if ((euid != 0) && (getuid() != euid)) { 598 error("control mode uid mismatch: peer euid %u != uid %u", 599 (u_int) euid, (u_int) getuid()); 600 close(client_fd); 601 return; 602 } 603 604 allowed = 1; 605 if (options.control_master == 2) { 606 char *p, prompt[1024]; 607 608 allowed = 0; 609 snprintf(prompt, sizeof(prompt), 610 "Allow shared connection to %s? ", host); 611 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF); 612 if (p != NULL) { 613 /* 614 * Accept empty responses and responses consisting 615 * of the word "yes" as affirmative. 616 */ 617 if (*p == '\0' || *p == '\n' || 618 strcasecmp(p, "yes") == 0) 619 allowed = 1; 620 xfree(p); 621 } 622 } 623 624 unset_nonblock(client_fd); 625 626 buffer_init(&m); 627 628 buffer_put_int(&m, allowed); 629 buffer_put_int(&m, getpid()); 630 if (ssh_msg_send(client_fd, /* version */0, &m) == -1) { 631 error("%s: client msg_send failed", __func__); 632 close(client_fd); 633 buffer_free(&m); 634 return; 635 } 636 buffer_clear(&m); 637 638 if (!allowed) { 639 error("Refused control connection"); 640 close(client_fd); 641 buffer_free(&m); 642 return; 643 } 644 645 if (ssh_msg_recv(client_fd, &m) == -1) { 646 error("%s: client msg_recv failed", __func__); 647 close(client_fd); 648 buffer_free(&m); 649 return; 650 } 651 652 if ((ver = buffer_get_char(&m)) != 0) { 653 error("%s: wrong client version %d", __func__, ver); 654 buffer_free(&m); 655 close(client_fd); 656 return; 657 } 658 659 cctx = xmalloc(sizeof(*cctx)); 660 memset(cctx, 0, sizeof(*cctx)); 661 662 cctx->want_tty = buffer_get_int(&m); 663 cctx->want_subsys = buffer_get_int(&m); 664 cctx->term = buffer_get_string(&m, &len); 665 666 cmd = buffer_get_string(&m, &len); 667 buffer_init(&cctx->cmd); 668 buffer_append(&cctx->cmd, cmd, strlen(cmd)); 669 670 env_len = buffer_get_int(&m); 671 env_len = MIN(env_len, 4096); 672 debug3("%s: receiving %d env vars", __func__, env_len); 673 if (env_len != 0) { 674 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1)); 675 for (i = 0; i < env_len; i++) 676 cctx->env[i] = buffer_get_string(&m, &len); 677 cctx->env[i] = NULL; 678 } 679 680 debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__, 681 cctx->want_tty, cctx->want_subsys, cmd); 682 683 /* Gather fds from client */ 684 new_fd[0] = mm_receive_fd(client_fd); 685 new_fd[1] = mm_receive_fd(client_fd); 686 new_fd[2] = mm_receive_fd(client_fd); 687 688 debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__, 689 new_fd[0], new_fd[1], new_fd[2]); 690 691 /* Try to pick up ttymodes from client before it goes raw */ 692 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1) 693 error("%s: tcgetattr: %s", __func__, strerror(errno)); 694 695 buffer_clear(&m); 696 if (ssh_msg_send(client_fd, /* version */0, &m) == -1) { 697 error("%s: client msg_send failed", __func__); 698 close(client_fd); 699 close(new_fd[0]); 700 close(new_fd[1]); 701 close(new_fd[2]); 702 buffer_free(&m); 703 return; 704 } 705 buffer_free(&m); 706 707 /* enable nonblocking unless tty */ 708 if (!isatty(new_fd[0])) 709 set_nonblock(new_fd[0]); 710 if (!isatty(new_fd[1])) 711 set_nonblock(new_fd[1]); 712 if (!isatty(new_fd[2])) 713 set_nonblock(new_fd[2]); 714 715 set_nonblock(client_fd); 716 717 c = channel_new("session", SSH_CHANNEL_OPENING, 718 new_fd[0], new_fd[1], new_fd[2], 719 CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT, 720 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 721 722 /* XXX */ 723 c->ctl_fd = client_fd; 724 725 debug3("%s: channel_new: %d", __func__, c->self); 726 727 channel_send_open(c->self); 728 channel_register_confirm(c->self, client_extra_session2_setup, cctx); 729 } 730 731 static void 732 process_cmdline(void) 733 { 734 void (*handler)(int); 735 char *s, *cmd; 736 u_short fwd_port, fwd_host_port; 737 char buf[1024], sfwd_port[6], sfwd_host_port[6]; 738 int delete = 0; 739 int local = 0; 740 741 leave_raw_mode(); 742 handler = signal(SIGINT, SIG_IGN); 743 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 744 if (s == NULL) 745 goto out; 746 while (*s && isspace(*s)) 747 s++; 748 if (*s == '-') 749 s++; /* Skip cmdline '-', if any */ 750 if (*s == '\0') 751 goto out; 752 753 if (*s == 'h' || *s == 'H' || *s == '?') { 754 logit("Commands:"); 755 logit(" -Lport:host:hostport Request local forward"); 756 logit(" -Rport:host:hostport Request remote forward"); 757 logit(" -KRhostport Cancel remote forward"); 758 goto out; 759 } 760 761 if (*s == 'K') { 762 delete = 1; 763 s++; 764 } 765 if (*s != 'L' && *s != 'R') { 766 logit("Invalid command."); 767 goto out; 768 } 769 if (*s == 'L') 770 local = 1; 771 if (local && delete) { 772 logit("Not supported."); 773 goto out; 774 } 775 if ((!local || delete) && !compat20) { 776 logit("Not supported for SSH protocol version 1."); 777 goto out; 778 } 779 780 s++; 781 while (*s && isspace(*s)) 782 s++; 783 784 if (delete) { 785 if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) { 786 logit("Bad forwarding specification."); 787 goto out; 788 } 789 if ((fwd_host_port = a2port(sfwd_host_port)) == 0) { 790 logit("Bad forwarding port(s)."); 791 goto out; 792 } 793 channel_request_rforward_cancel(fwd_host_port); 794 } else { 795 if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]", 796 sfwd_port, buf, sfwd_host_port) != 3 && 797 sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]", 798 sfwd_port, buf, sfwd_host_port) != 3) { 799 logit("Bad forwarding specification."); 800 goto out; 801 } 802 if ((fwd_port = a2port(sfwd_port)) == 0 || 803 (fwd_host_port = a2port(sfwd_host_port)) == 0) { 804 logit("Bad forwarding port(s)."); 805 goto out; 806 } 807 if (local) { 808 if (channel_setup_local_fwd_listener(fwd_port, buf, 809 fwd_host_port, options.gateway_ports) < 0) { 810 logit("Port forwarding failed."); 811 goto out; 812 } 813 } else 814 channel_request_remote_forwarding(fwd_port, buf, 815 fwd_host_port); 816 logit("Forwarding port."); 817 } 818 819 out: 820 signal(SIGINT, handler); 821 enter_raw_mode(); 822 if (cmd) 823 xfree(cmd); 824 } 825 826 /* process the characters one by one */ 827 static int 828 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) 829 { 830 char string[1024]; 831 pid_t pid; 832 int bytes = 0; 833 u_int i; 834 u_char ch; 835 char *s; 836 837 for (i = 0; i < len; i++) { 838 /* Get one character at a time. */ 839 ch = buf[i]; 840 841 if (escape_pending) { 842 /* We have previously seen an escape character. */ 843 /* Clear the flag now. */ 844 escape_pending = 0; 845 846 /* Process the escaped character. */ 847 switch (ch) { 848 case '.': 849 /* Terminate the connection. */ 850 snprintf(string, sizeof string, "%c.\r\n", escape_char); 851 buffer_append(berr, string, strlen(string)); 852 853 quit_pending = 1; 854 return -1; 855 856 case 'Z' - 64: 857 /* Suspend the program. */ 858 /* Print a message to that effect to the user. */ 859 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); 860 buffer_append(berr, string, strlen(string)); 861 862 /* Restore terminal modes and suspend. */ 863 client_suspend_self(bin, bout, berr); 864 865 /* We have been continued. */ 866 continue; 867 868 case 'B': 869 if (compat20) { 870 snprintf(string, sizeof string, 871 "%cB\r\n", escape_char); 872 buffer_append(berr, string, 873 strlen(string)); 874 channel_request_start(session_ident, 875 "break", 0); 876 packet_put_int(1000); 877 packet_send(); 878 } 879 continue; 880 881 case 'R': 882 if (compat20) { 883 if (datafellows & SSH_BUG_NOREKEY) 884 logit("Server does not support re-keying"); 885 else 886 need_rekeying = 1; 887 } 888 continue; 889 890 case '&': 891 /* 892 * Detach the program (continue to serve connections, 893 * but put in background and no more new connections). 894 */ 895 /* Restore tty modes. */ 896 leave_raw_mode(); 897 898 /* Stop listening for new connections. */ 899 channel_stop_listening(); 900 901 snprintf(string, sizeof string, 902 "%c& [backgrounded]\n", escape_char); 903 buffer_append(berr, string, strlen(string)); 904 905 /* Fork into background. */ 906 pid = fork(); 907 if (pid < 0) { 908 error("fork: %.100s", strerror(errno)); 909 continue; 910 } 911 if (pid != 0) { /* This is the parent. */ 912 /* The parent just exits. */ 913 exit(0); 914 } 915 /* The child continues serving connections. */ 916 if (compat20) { 917 buffer_append(bin, "\004", 1); 918 /* fake EOF on stdin */ 919 return -1; 920 } else if (!stdin_eof) { 921 /* 922 * Sending SSH_CMSG_EOF alone does not always appear 923 * to be enough. So we try to send an EOF character 924 * first. 925 */ 926 packet_start(SSH_CMSG_STDIN_DATA); 927 packet_put_string("\004", 1); 928 packet_send(); 929 /* Close stdin. */ 930 stdin_eof = 1; 931 if (buffer_len(bin) == 0) { 932 packet_start(SSH_CMSG_EOF); 933 packet_send(); 934 } 935 } 936 continue; 937 938 case '?': 939 snprintf(string, sizeof string, 940 "%c?\r\n\ 941 Supported escape sequences:\r\n\ 942 %c. - terminate connection\r\n\ 943 %cB - send a BREAK to the remote system\r\n\ 944 %cC - open a command line\r\n\ 945 %cR - Request rekey (SSH protocol 2 only)\r\n\ 946 %c^Z - suspend ssh\r\n\ 947 %c# - list forwarded connections\r\n\ 948 %c& - background ssh (when waiting for connections to terminate)\r\n\ 949 %c? - this message\r\n\ 950 %c%c - send the escape character by typing it twice\r\n\ 951 (Note that escapes are only recognized immediately after newline.)\r\n", 952 escape_char, escape_char, escape_char, escape_char, 953 escape_char, escape_char, escape_char, escape_char, 954 escape_char, escape_char, escape_char); 955 buffer_append(berr, string, strlen(string)); 956 continue; 957 958 case '#': 959 snprintf(string, sizeof string, "%c#\r\n", escape_char); 960 buffer_append(berr, string, strlen(string)); 961 s = channel_open_message(); 962 buffer_append(berr, s, strlen(s)); 963 xfree(s); 964 continue; 965 966 case 'C': 967 process_cmdline(); 968 continue; 969 970 default: 971 if (ch != escape_char) { 972 buffer_put_char(bin, escape_char); 973 bytes++; 974 } 975 /* Escaped characters fall through here */ 976 break; 977 } 978 } else { 979 /* 980 * The previous character was not an escape char. Check if this 981 * is an escape. 982 */ 983 if (last_was_cr && ch == escape_char) { 984 /* It is. Set the flag and continue to next character. */ 985 escape_pending = 1; 986 continue; 987 } 988 } 989 990 /* 991 * Normal character. Record whether it was a newline, 992 * and append it to the buffer. 993 */ 994 last_was_cr = (ch == '\r' || ch == '\n'); 995 buffer_put_char(bin, ch); 996 bytes++; 997 } 998 return bytes; 999 } 1000 1001 static void 1002 client_process_input(fd_set * readset) 1003 { 1004 int len; 1005 char buf[8192]; 1006 1007 /* Read input from stdin. */ 1008 if (FD_ISSET(fileno(stdin), readset)) { 1009 /* Read as much as possible. */ 1010 len = read(fileno(stdin), buf, sizeof(buf)); 1011 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 1012 return; /* we'll try again later */ 1013 if (len <= 0) { 1014 /* 1015 * Received EOF or error. They are treated 1016 * similarly, except that an error message is printed 1017 * if it was an error condition. 1018 */ 1019 if (len < 0) { 1020 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); 1021 buffer_append(&stderr_buffer, buf, strlen(buf)); 1022 } 1023 /* Mark that we have seen EOF. */ 1024 stdin_eof = 1; 1025 /* 1026 * Send an EOF message to the server unless there is 1027 * data in the buffer. If there is data in the 1028 * buffer, no message will be sent now. Code 1029 * elsewhere will send the EOF when the buffer 1030 * becomes empty if stdin_eof is set. 1031 */ 1032 if (buffer_len(&stdin_buffer) == 0) { 1033 packet_start(SSH_CMSG_EOF); 1034 packet_send(); 1035 } 1036 } else if (escape_char == SSH_ESCAPECHAR_NONE) { 1037 /* 1038 * Normal successful read, and no escape character. 1039 * Just append the data to buffer. 1040 */ 1041 buffer_append(&stdin_buffer, buf, len); 1042 } else { 1043 /* 1044 * Normal, successful read. But we have an escape character 1045 * and have to process the characters one by one. 1046 */ 1047 if (process_escapes(&stdin_buffer, &stdout_buffer, 1048 &stderr_buffer, buf, len) == -1) 1049 return; 1050 } 1051 } 1052 } 1053 1054 static void 1055 client_process_output(fd_set * writeset) 1056 { 1057 int len; 1058 char buf[100]; 1059 1060 /* Write buffered output to stdout. */ 1061 if (FD_ISSET(fileno(stdout), writeset)) { 1062 /* Write as much data as possible. */ 1063 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1064 buffer_len(&stdout_buffer)); 1065 if (len <= 0) { 1066 if (errno == EINTR || errno == EAGAIN) 1067 len = 0; 1068 else { 1069 /* 1070 * An error or EOF was encountered. Put an 1071 * error message to stderr buffer. 1072 */ 1073 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); 1074 buffer_append(&stderr_buffer, buf, strlen(buf)); 1075 quit_pending = 1; 1076 return; 1077 } 1078 } 1079 /* Consume printed data from the buffer. */ 1080 buffer_consume(&stdout_buffer, len); 1081 stdout_bytes += len; 1082 } 1083 /* Write buffered output to stderr. */ 1084 if (FD_ISSET(fileno(stderr), writeset)) { 1085 /* Write as much data as possible. */ 1086 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1087 buffer_len(&stderr_buffer)); 1088 if (len <= 0) { 1089 if (errno == EINTR || errno == EAGAIN) 1090 len = 0; 1091 else { 1092 /* EOF or error, but can't even print error message. */ 1093 quit_pending = 1; 1094 return; 1095 } 1096 } 1097 /* Consume printed characters from the buffer. */ 1098 buffer_consume(&stderr_buffer, len); 1099 stderr_bytes += len; 1100 } 1101 } 1102 1103 /* 1104 * Get packets from the connection input buffer, and process them as long as 1105 * there are packets available. 1106 * 1107 * Any unknown packets received during the actual 1108 * session cause the session to terminate. This is 1109 * intended to make debugging easier since no 1110 * confirmations are sent. Any compatible protocol 1111 * extensions must be negotiated during the 1112 * preparatory phase. 1113 */ 1114 1115 static void 1116 client_process_buffered_input_packets(void) 1117 { 1118 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL); 1119 } 1120 1121 /* scan buf[] for '~' before sending data to the peer */ 1122 1123 static int 1124 simple_escape_filter(Channel *c, char *buf, int len) 1125 { 1126 /* XXX we assume c->extended is writeable */ 1127 return process_escapes(&c->input, &c->output, &c->extended, buf, len); 1128 } 1129 1130 static void 1131 client_channel_closed(int id, void *arg) 1132 { 1133 channel_cancel_cleanup(id); 1134 session_closed = 1; 1135 leave_raw_mode(); 1136 } 1137 1138 /* 1139 * Implements the interactive session with the server. This is called after 1140 * the user has been authenticated, and a command has been started on the 1141 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1142 * used as an escape character for terminating or suspending the session. 1143 */ 1144 1145 int 1146 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1147 { 1148 fd_set *readset = NULL, *writeset = NULL; 1149 double start_time, total_time; 1150 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1151 u_int nalloc = 0; 1152 char buf[100]; 1153 1154 debug("Entering interactive session."); 1155 1156 start_time = get_current_time(); 1157 1158 /* Initialize variables. */ 1159 escape_pending = 0; 1160 last_was_cr = 1; 1161 exit_status = -1; 1162 stdin_eof = 0; 1163 buffer_high = 64 * 1024; 1164 connection_in = packet_get_connection_in(); 1165 connection_out = packet_get_connection_out(); 1166 max_fd = MAX(connection_in, connection_out); 1167 if (control_fd != -1) 1168 max_fd = MAX(max_fd, control_fd); 1169 1170 if (!compat20) { 1171 /* enable nonblocking unless tty */ 1172 if (!isatty(fileno(stdin))) 1173 set_nonblock(fileno(stdin)); 1174 if (!isatty(fileno(stdout))) 1175 set_nonblock(fileno(stdout)); 1176 if (!isatty(fileno(stderr))) 1177 set_nonblock(fileno(stderr)); 1178 max_fd = MAX(max_fd, fileno(stdin)); 1179 max_fd = MAX(max_fd, fileno(stdout)); 1180 max_fd = MAX(max_fd, fileno(stderr)); 1181 } 1182 stdin_bytes = 0; 1183 stdout_bytes = 0; 1184 stderr_bytes = 0; 1185 quit_pending = 0; 1186 escape_char = escape_char_arg; 1187 1188 /* Initialize buffers. */ 1189 buffer_init(&stdin_buffer); 1190 buffer_init(&stdout_buffer); 1191 buffer_init(&stderr_buffer); 1192 1193 client_init_dispatch(); 1194 1195 /* 1196 * Set signal handlers, (e.g. to restore non-blocking mode) 1197 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1198 */ 1199 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1200 signal(SIGINT, signal_handler); 1201 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1202 signal(SIGQUIT, signal_handler); 1203 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1204 signal(SIGTERM, signal_handler); 1205 if (have_pty) 1206 signal(SIGWINCH, window_change_handler); 1207 1208 if (have_pty) 1209 enter_raw_mode(); 1210 1211 if (compat20) { 1212 session_ident = ssh2_chan_id; 1213 if (escape_char != SSH_ESCAPECHAR_NONE) 1214 channel_register_filter(session_ident, 1215 simple_escape_filter); 1216 if (session_ident != -1) 1217 channel_register_cleanup(session_ident, 1218 client_channel_closed); 1219 } else { 1220 /* Check if we should immediately send eof on stdin. */ 1221 client_check_initial_eof_on_stdin(); 1222 } 1223 1224 /* Main loop of the client for the interactive session mode. */ 1225 while (!quit_pending) { 1226 1227 /* Process buffered packets sent by the server. */ 1228 client_process_buffered_input_packets(); 1229 1230 if (compat20 && session_closed && !channel_still_open()) 1231 break; 1232 1233 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1234 1235 if (rekeying) { 1236 debug("rekeying in progress"); 1237 } else { 1238 /* 1239 * Make packets of buffered stdin data, and buffer 1240 * them for sending to the server. 1241 */ 1242 if (!compat20) 1243 client_make_packets_from_stdin_data(); 1244 1245 /* 1246 * Make packets from buffered channel data, and 1247 * enqueue them for sending to the server. 1248 */ 1249 if (packet_not_very_much_data_to_write()) 1250 channel_output_poll(); 1251 1252 /* 1253 * Check if the window size has changed, and buffer a 1254 * message about it to the server if so. 1255 */ 1256 client_check_window_change(); 1257 1258 if (quit_pending) 1259 break; 1260 } 1261 /* 1262 * Wait until we have something to do (something becomes 1263 * available on one of the descriptors). 1264 */ 1265 max_fd2 = max_fd; 1266 client_wait_until_can_do_something(&readset, &writeset, 1267 &max_fd2, &nalloc, rekeying); 1268 1269 if (quit_pending) 1270 break; 1271 1272 /* Do channel operations unless rekeying in progress. */ 1273 if (!rekeying) { 1274 channel_after_select(readset, writeset); 1275 if (need_rekeying || packet_need_rekeying()) { 1276 debug("need rekeying"); 1277 xxx_kex->done = 0; 1278 kex_send_kexinit(xxx_kex); 1279 need_rekeying = 0; 1280 } 1281 } 1282 1283 /* Buffer input from the connection. */ 1284 client_process_net_input(readset); 1285 1286 /* Accept control connections. */ 1287 client_process_control(readset); 1288 1289 if (quit_pending) 1290 break; 1291 1292 if (!compat20) { 1293 /* Buffer data from stdin */ 1294 client_process_input(readset); 1295 /* 1296 * Process output to stdout and stderr. Output to 1297 * the connection is processed elsewhere (above). 1298 */ 1299 client_process_output(writeset); 1300 } 1301 1302 /* Send as much buffered packet data as possible to the sender. */ 1303 if (FD_ISSET(connection_out, writeset)) 1304 packet_write_poll(); 1305 } 1306 if (readset) 1307 xfree(readset); 1308 if (writeset) 1309 xfree(writeset); 1310 1311 /* Terminate the session. */ 1312 1313 /* Stop watching for window change. */ 1314 if (have_pty) 1315 signal(SIGWINCH, SIG_DFL); 1316 1317 channel_free_all(); 1318 1319 if (have_pty) 1320 leave_raw_mode(); 1321 1322 /* restore blocking io */ 1323 if (!isatty(fileno(stdin))) 1324 unset_nonblock(fileno(stdin)); 1325 if (!isatty(fileno(stdout))) 1326 unset_nonblock(fileno(stdout)); 1327 if (!isatty(fileno(stderr))) 1328 unset_nonblock(fileno(stderr)); 1329 1330 /* 1331 * If there was no shell or command requested, there will be no remote 1332 * exit status to be returned. In that case, clear error code if the 1333 * connection was deliberately terminated at this end. 1334 */ 1335 if (no_shell_flag && received_signal == SIGTERM) { 1336 received_signal = 0; 1337 exit_status = 0; 1338 } 1339 1340 if (received_signal) 1341 fatal("Killed by signal %d.", (int) received_signal); 1342 1343 /* 1344 * In interactive mode (with pseudo tty) display a message indicating 1345 * that the connection has been closed. 1346 */ 1347 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1348 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); 1349 buffer_append(&stderr_buffer, buf, strlen(buf)); 1350 } 1351 1352 /* Output any buffered data for stdout. */ 1353 while (buffer_len(&stdout_buffer) > 0) { 1354 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1355 buffer_len(&stdout_buffer)); 1356 if (len <= 0) { 1357 error("Write failed flushing stdout buffer."); 1358 break; 1359 } 1360 buffer_consume(&stdout_buffer, len); 1361 stdout_bytes += len; 1362 } 1363 1364 /* Output any buffered data for stderr. */ 1365 while (buffer_len(&stderr_buffer) > 0) { 1366 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1367 buffer_len(&stderr_buffer)); 1368 if (len <= 0) { 1369 error("Write failed flushing stderr buffer."); 1370 break; 1371 } 1372 buffer_consume(&stderr_buffer, len); 1373 stderr_bytes += len; 1374 } 1375 1376 /* Clear and free any buffers. */ 1377 memset(buf, 0, sizeof(buf)); 1378 buffer_free(&stdin_buffer); 1379 buffer_free(&stdout_buffer); 1380 buffer_free(&stderr_buffer); 1381 1382 /* Report bytes transferred, and transfer rates. */ 1383 total_time = get_current_time() - start_time; 1384 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", 1385 stdin_bytes, stdout_bytes, stderr_bytes, total_time); 1386 if (total_time > 0) 1387 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", 1388 stdin_bytes / total_time, stdout_bytes / total_time, 1389 stderr_bytes / total_time); 1390 1391 /* Return the exit status of the program. */ 1392 debug("Exit status %d", exit_status); 1393 return exit_status; 1394 } 1395 1396 /*********/ 1397 1398 static void 1399 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1400 { 1401 u_int data_len; 1402 char *data = packet_get_string(&data_len); 1403 packet_check_eom(); 1404 buffer_append(&stdout_buffer, data, data_len); 1405 memset(data, 0, data_len); 1406 xfree(data); 1407 } 1408 static void 1409 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1410 { 1411 u_int data_len; 1412 char *data = packet_get_string(&data_len); 1413 packet_check_eom(); 1414 buffer_append(&stderr_buffer, data, data_len); 1415 memset(data, 0, data_len); 1416 xfree(data); 1417 } 1418 static void 1419 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1420 { 1421 exit_status = packet_get_int(); 1422 packet_check_eom(); 1423 /* Acknowledge the exit. */ 1424 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1425 packet_send(); 1426 /* 1427 * Must wait for packet to be sent since we are 1428 * exiting the loop. 1429 */ 1430 packet_write_wait(); 1431 /* Flag that we want to exit. */ 1432 quit_pending = 1; 1433 } 1434 static void 1435 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1436 { 1437 Channel *c = NULL; 1438 int remote_id, sock; 1439 1440 /* Read the remote channel number from the message. */ 1441 remote_id = packet_get_int(); 1442 packet_check_eom(); 1443 1444 /* 1445 * Get a connection to the local authentication agent (this may again 1446 * get forwarded). 1447 */ 1448 sock = ssh_get_authentication_socket(); 1449 1450 /* 1451 * If we could not connect the agent, send an error message back to 1452 * the server. This should never happen unless the agent dies, 1453 * because authentication forwarding is only enabled if we have an 1454 * agent. 1455 */ 1456 if (sock >= 0) { 1457 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1458 -1, 0, 0, 0, "authentication agent connection", 1); 1459 c->remote_id = remote_id; 1460 c->force_drain = 1; 1461 } 1462 if (c == NULL) { 1463 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1464 packet_put_int(remote_id); 1465 } else { 1466 /* Send a confirmation to the remote host. */ 1467 debug("Forwarding authentication connection."); 1468 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1469 packet_put_int(remote_id); 1470 packet_put_int(c->self); 1471 } 1472 packet_send(); 1473 } 1474 1475 static Channel * 1476 client_request_forwarded_tcpip(const char *request_type, int rchan) 1477 { 1478 Channel *c = NULL; 1479 char *listen_address, *originator_address; 1480 int listen_port, originator_port; 1481 int sock; 1482 1483 /* Get rest of the packet */ 1484 listen_address = packet_get_string(NULL); 1485 listen_port = packet_get_int(); 1486 originator_address = packet_get_string(NULL); 1487 originator_port = packet_get_int(); 1488 packet_check_eom(); 1489 1490 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d", 1491 listen_address, listen_port, originator_address, originator_port); 1492 1493 sock = channel_connect_by_listen_address(listen_port); 1494 if (sock < 0) { 1495 xfree(originator_address); 1496 xfree(listen_address); 1497 return NULL; 1498 } 1499 c = channel_new("forwarded-tcpip", 1500 SSH_CHANNEL_CONNECTING, sock, sock, -1, 1501 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1502 originator_address, 1); 1503 xfree(originator_address); 1504 xfree(listen_address); 1505 return c; 1506 } 1507 1508 static Channel * 1509 client_request_x11(const char *request_type, int rchan) 1510 { 1511 Channel *c = NULL; 1512 char *originator; 1513 int originator_port; 1514 int sock; 1515 1516 if (!options.forward_x11) { 1517 error("Warning: ssh server tried X11 forwarding."); 1518 error("Warning: this is probably a break in attempt by a malicious server."); 1519 return NULL; 1520 } 1521 originator = packet_get_string(NULL); 1522 if (datafellows & SSH_BUG_X11FWD) { 1523 debug2("buggy server: x11 request w/o originator_port"); 1524 originator_port = 0; 1525 } else { 1526 originator_port = packet_get_int(); 1527 } 1528 packet_check_eom(); 1529 /* XXX check permission */ 1530 debug("client_request_x11: request from %s %d", originator, 1531 originator_port); 1532 xfree(originator); 1533 sock = x11_connect_display(); 1534 if (sock < 0) 1535 return NULL; 1536 c = channel_new("x11", 1537 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1538 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1539 c->force_drain = 1; 1540 return c; 1541 } 1542 1543 static Channel * 1544 client_request_agent(const char *request_type, int rchan) 1545 { 1546 Channel *c = NULL; 1547 int sock; 1548 1549 if (!options.forward_agent) { 1550 error("Warning: ssh server tried agent forwarding."); 1551 error("Warning: this is probably a break in attempt by a malicious server."); 1552 return NULL; 1553 } 1554 sock = ssh_get_authentication_socket(); 1555 if (sock < 0) 1556 return NULL; 1557 c = channel_new("authentication agent connection", 1558 SSH_CHANNEL_OPEN, sock, sock, -1, 1559 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1560 "authentication agent connection", 1); 1561 c->force_drain = 1; 1562 return c; 1563 } 1564 1565 /* XXXX move to generic input handler */ 1566 static void 1567 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1568 { 1569 Channel *c = NULL; 1570 char *ctype; 1571 int rchan; 1572 u_int rmaxpack, rwindow, len; 1573 1574 ctype = packet_get_string(&len); 1575 rchan = packet_get_int(); 1576 rwindow = packet_get_int(); 1577 rmaxpack = packet_get_int(); 1578 1579 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1580 ctype, rchan, rwindow, rmaxpack); 1581 1582 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1583 c = client_request_forwarded_tcpip(ctype, rchan); 1584 } else if (strcmp(ctype, "x11") == 0) { 1585 c = client_request_x11(ctype, rchan); 1586 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1587 c = client_request_agent(ctype, rchan); 1588 } 1589 /* XXX duplicate : */ 1590 if (c != NULL) { 1591 debug("confirm %s", ctype); 1592 c->remote_id = rchan; 1593 c->remote_window = rwindow; 1594 c->remote_maxpacket = rmaxpack; 1595 if (c->type != SSH_CHANNEL_CONNECTING) { 1596 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1597 packet_put_int(c->remote_id); 1598 packet_put_int(c->self); 1599 packet_put_int(c->local_window); 1600 packet_put_int(c->local_maxpacket); 1601 packet_send(); 1602 } 1603 } else { 1604 debug("failure %s", ctype); 1605 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1606 packet_put_int(rchan); 1607 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1608 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1609 packet_put_cstring("open failed"); 1610 packet_put_cstring(""); 1611 } 1612 packet_send(); 1613 } 1614 xfree(ctype); 1615 } 1616 static void 1617 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1618 { 1619 Channel *c = NULL; 1620 int exitval, id, reply, success = 0; 1621 char *rtype; 1622 1623 id = packet_get_int(); 1624 rtype = packet_get_string(NULL); 1625 reply = packet_get_char(); 1626 1627 debug("client_input_channel_req: channel %d rtype %s reply %d", 1628 id, rtype, reply); 1629 1630 if (id == -1) { 1631 error("client_input_channel_req: request for channel -1"); 1632 } else if ((c = channel_lookup(id)) == NULL) { 1633 error("client_input_channel_req: channel %d: unknown channel", id); 1634 } else if (strcmp(rtype, "exit-status") == 0) { 1635 exitval = packet_get_int(); 1636 if (id == session_ident) { 1637 success = 1; 1638 exit_status = exitval; 1639 } else if (c->ctl_fd == -1) { 1640 error("client_input_channel_req: unexpected channel %d", 1641 session_ident); 1642 } else { 1643 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1644 success = 1; 1645 } 1646 packet_check_eom(); 1647 } 1648 if (reply) { 1649 packet_start(success ? 1650 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1651 packet_put_int(id); 1652 packet_send(); 1653 } 1654 xfree(rtype); 1655 } 1656 static void 1657 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1658 { 1659 char *rtype; 1660 int want_reply; 1661 int success = 0; 1662 1663 rtype = packet_get_string(NULL); 1664 want_reply = packet_get_char(); 1665 debug("client_input_global_request: rtype %s want_reply %d", 1666 rtype, want_reply); 1667 if (want_reply) { 1668 packet_start(success ? 1669 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1670 packet_send(); 1671 packet_write_wait(); 1672 } 1673 xfree(rtype); 1674 } 1675 1676 void 1677 client_session2_setup(int id, int want_tty, int want_subsystem, 1678 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env, 1679 dispatch_fn *subsys_repl) 1680 { 1681 int len; 1682 1683 debug2("%s: id %d", __func__, id); 1684 1685 if (want_tty) { 1686 struct winsize ws; 1687 struct termios tio; 1688 1689 /* Store window size in the packet. */ 1690 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1691 memset(&ws, 0, sizeof(ws)); 1692 1693 channel_request_start(id, "pty-req", 0); 1694 packet_put_cstring(term != NULL ? term : ""); 1695 packet_put_int(ws.ws_col); 1696 packet_put_int(ws.ws_row); 1697 packet_put_int(ws.ws_xpixel); 1698 packet_put_int(ws.ws_ypixel); 1699 tio = get_saved_tio(); 1700 tty_make_modes(-1, tiop != NULL ? tiop : &tio); 1701 packet_send(); 1702 /* XXX wait for reply */ 1703 } 1704 1705 /* Transfer any environment variables from client to server */ 1706 if (options.num_send_env != 0 && env != NULL) { 1707 int i, j, matched; 1708 char *name, *val; 1709 1710 debug("Sending environment."); 1711 for (i = 0; env[i] != NULL; i++) { 1712 /* Split */ 1713 name = xstrdup(env[i]); 1714 if ((val = strchr(name, '=')) == NULL) { 1715 free(name); 1716 continue; 1717 } 1718 *val++ = '\0'; 1719 1720 matched = 0; 1721 for (j = 0; j < options.num_send_env; j++) { 1722 if (match_pattern(name, options.send_env[j])) { 1723 matched = 1; 1724 break; 1725 } 1726 } 1727 if (!matched) { 1728 debug3("Ignored env %s", name); 1729 free(name); 1730 continue; 1731 } 1732 1733 debug("Sending env %s = %s", name, val); 1734 channel_request_start(id, "env", 0); 1735 packet_put_cstring(name); 1736 packet_put_cstring(val); 1737 packet_send(); 1738 free(name); 1739 } 1740 } 1741 1742 len = buffer_len(cmd); 1743 if (len > 0) { 1744 if (len > 900) 1745 len = 900; 1746 if (want_subsystem) { 1747 debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd)); 1748 channel_request_start(id, "subsystem", subsys_repl != NULL); 1749 if (subsys_repl != NULL) { 1750 /* register callback for reply */ 1751 /* XXX we assume that client_loop has already been called */ 1752 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl); 1753 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl); 1754 } 1755 } else { 1756 debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd)); 1757 channel_request_start(id, "exec", 0); 1758 } 1759 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1760 packet_send(); 1761 } else { 1762 channel_request_start(id, "shell", 0); 1763 packet_send(); 1764 } 1765 } 1766 1767 static void 1768 client_init_dispatch_20(void) 1769 { 1770 dispatch_init(&dispatch_protocol_error); 1771 1772 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1773 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1774 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1775 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1776 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1777 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1778 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1779 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1780 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1781 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1782 1783 /* rekeying */ 1784 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1785 1786 /* global request reply messages */ 1787 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 1788 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 1789 } 1790 static void 1791 client_init_dispatch_13(void) 1792 { 1793 dispatch_init(NULL); 1794 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 1795 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 1796 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 1797 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1798 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1799 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 1800 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 1801 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 1802 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 1803 1804 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 1805 &client_input_agent_open : &deny_input_open); 1806 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 1807 &x11_input_open : &deny_input_open); 1808 } 1809 static void 1810 client_init_dispatch_15(void) 1811 { 1812 client_init_dispatch_13(); 1813 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 1814 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 1815 } 1816 static void 1817 client_init_dispatch(void) 1818 { 1819 if (compat20) 1820 client_init_dispatch_20(); 1821 else if (compat13) 1822 client_init_dispatch_13(); 1823 else 1824 client_init_dispatch_15(); 1825 } 1826 1827 /* client specific fatal cleanup */ 1828 void 1829 cleanup_exit(int i) 1830 { 1831 leave_raw_mode(); 1832 leave_non_blocking(); 1833 if (options.control_path != NULL && control_fd != -1) 1834 unlink(options.control_path); 1835 _exit(i); 1836 } 1837