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 1.136 2005/03/10 22:01:05 deraadt 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 /* Flush stdout and stderr buffers. */ 436 if (buffer_len(bout) > 0) 437 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout)); 438 if (buffer_len(berr) > 0) 439 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr)); 440 441 leave_raw_mode(); 442 443 /* 444 * Free (and clear) the buffer to reduce the amount of data that gets 445 * written to swap. 446 */ 447 buffer_free(bin); 448 buffer_free(bout); 449 buffer_free(berr); 450 451 /* Send the suspend signal to the program itself. */ 452 kill(getpid(), SIGTSTP); 453 454 /* Reset window sizes in case they have changed */ 455 received_window_change_signal = 1; 456 457 /* OK, we have been continued by the user. Reinitialize buffers. */ 458 buffer_init(bin); 459 buffer_init(bout); 460 buffer_init(berr); 461 462 enter_raw_mode(); 463 } 464 465 static void 466 client_process_net_input(fd_set * readset) 467 { 468 int len; 469 char buf[8192]; 470 471 /* 472 * Read input from the server, and add any such data to the buffer of 473 * the packet subsystem. 474 */ 475 if (FD_ISSET(connection_in, readset)) { 476 /* Read as much as possible. */ 477 len = read(connection_in, buf, sizeof(buf)); 478 if (len == 0) { 479 /* Received EOF. The remote host has closed the connection. */ 480 snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", 481 host); 482 buffer_append(&stderr_buffer, buf, strlen(buf)); 483 quit_pending = 1; 484 return; 485 } 486 /* 487 * There is a kernel bug on Solaris that causes select to 488 * sometimes wake up even though there is no data available. 489 */ 490 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 491 len = 0; 492 493 if (len < 0) { 494 /* An error has encountered. Perhaps there is a network problem. */ 495 snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", 496 host, strerror(errno)); 497 buffer_append(&stderr_buffer, buf, strlen(buf)); 498 quit_pending = 1; 499 return; 500 } 501 packet_process_incoming(buf, len); 502 } 503 } 504 505 static void 506 client_subsystem_reply(int type, u_int32_t seq, void *ctxt) 507 { 508 int id; 509 Channel *c; 510 511 id = packet_get_int(); 512 packet_check_eom(); 513 514 if ((c = channel_lookup(id)) == NULL) { 515 error("%s: no channel for id %d", __func__, id); 516 return; 517 } 518 519 if (type == SSH2_MSG_CHANNEL_SUCCESS) 520 debug2("Request suceeded on channel %d", id); 521 else if (type == SSH2_MSG_CHANNEL_FAILURE) { 522 error("Request failed on channel %d", id); 523 channel_free(c); 524 } 525 } 526 527 static void 528 client_extra_session2_setup(int id, void *arg) 529 { 530 struct confirm_ctx *cctx = arg; 531 Channel *c; 532 int i; 533 534 if (cctx == NULL) 535 fatal("%s: cctx == NULL", __func__); 536 if ((c = channel_lookup(id)) == NULL) 537 fatal("%s: no channel for id %d", __func__, id); 538 539 client_session2_setup(id, cctx->want_tty, cctx->want_subsys, 540 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env, 541 client_subsystem_reply); 542 543 c->confirm_ctx = NULL; 544 buffer_free(&cctx->cmd); 545 xfree(cctx->term); 546 if (cctx->env != NULL) { 547 for (i = 0; cctx->env[i] != NULL; i++) 548 xfree(cctx->env[i]); 549 xfree(cctx->env); 550 } 551 xfree(cctx); 552 } 553 554 static void 555 client_process_control(fd_set * readset) 556 { 557 Buffer m; 558 Channel *c; 559 int client_fd, new_fd[3], ver, i, allowed; 560 socklen_t addrlen; 561 struct sockaddr_storage addr; 562 struct confirm_ctx *cctx; 563 char *cmd; 564 u_int len, env_len, command, flags; 565 uid_t euid; 566 gid_t egid; 567 568 /* 569 * Accept connection on control socket 570 */ 571 if (control_fd == -1 || !FD_ISSET(control_fd, readset)) 572 return; 573 574 memset(&addr, 0, sizeof(addr)); 575 addrlen = sizeof(addr); 576 if ((client_fd = accept(control_fd, 577 (struct sockaddr*)&addr, &addrlen)) == -1) { 578 error("%s accept: %s", __func__, strerror(errno)); 579 return; 580 } 581 582 if (getpeereid(client_fd, &euid, &egid) < 0) { 583 error("%s getpeereid failed: %s", __func__, strerror(errno)); 584 close(client_fd); 585 return; 586 } 587 if ((euid != 0) && (getuid() != euid)) { 588 error("control mode uid mismatch: peer euid %u != uid %u", 589 (u_int) euid, (u_int) getuid()); 590 close(client_fd); 591 return; 592 } 593 594 unset_nonblock(client_fd); 595 596 /* Read command */ 597 buffer_init(&m); 598 if (ssh_msg_recv(client_fd, &m) == -1) { 599 error("%s: client msg_recv failed", __func__); 600 close(client_fd); 601 buffer_free(&m); 602 return; 603 } 604 if ((ver = buffer_get_char(&m)) != 1) { 605 error("%s: wrong client version %d", __func__, ver); 606 buffer_free(&m); 607 close(client_fd); 608 return; 609 } 610 611 allowed = 1; 612 command = buffer_get_int(&m); 613 flags = buffer_get_int(&m); 614 615 buffer_clear(&m); 616 617 switch (command) { 618 case SSHMUX_COMMAND_OPEN: 619 if (options.control_master == 2) 620 allowed = ask_permission("Allow shared connection " 621 "to %s? ", host); 622 /* continue below */ 623 break; 624 case SSHMUX_COMMAND_TERMINATE: 625 if (options.control_master == 2) 626 allowed = ask_permission("Terminate shared connection " 627 "to %s? ", host); 628 if (allowed) 629 quit_pending = 1; 630 /* FALLTHROUGH */ 631 case SSHMUX_COMMAND_ALIVE_CHECK: 632 /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */ 633 buffer_clear(&m); 634 buffer_put_int(&m, allowed); 635 buffer_put_int(&m, getpid()); 636 if (ssh_msg_send(client_fd, /* version */1, &m) == -1) { 637 error("%s: client msg_send failed", __func__); 638 close(client_fd); 639 buffer_free(&m); 640 return; 641 } 642 buffer_free(&m); 643 close(client_fd); 644 return; 645 default: 646 error("Unsupported command %d", command); 647 buffer_free(&m); 648 close(client_fd); 649 return; 650 } 651 652 /* Reply for SSHMUX_COMMAND_OPEN */ 653 buffer_clear(&m); 654 buffer_put_int(&m, allowed); 655 buffer_put_int(&m, getpid()); 656 if (ssh_msg_send(client_fd, /* version */1, &m) == -1) { 657 error("%s: client msg_send failed", __func__); 658 close(client_fd); 659 buffer_free(&m); 660 return; 661 } 662 663 if (!allowed) { 664 error("Refused control connection"); 665 close(client_fd); 666 buffer_free(&m); 667 return; 668 } 669 670 buffer_clear(&m); 671 if (ssh_msg_recv(client_fd, &m) == -1) { 672 error("%s: client msg_recv failed", __func__); 673 close(client_fd); 674 buffer_free(&m); 675 return; 676 } 677 if ((ver = buffer_get_char(&m)) != 1) { 678 error("%s: wrong client version %d", __func__, ver); 679 buffer_free(&m); 680 close(client_fd); 681 return; 682 } 683 684 cctx = xmalloc(sizeof(*cctx)); 685 memset(cctx, 0, sizeof(*cctx)); 686 cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0; 687 cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0; 688 cctx->term = buffer_get_string(&m, &len); 689 690 cmd = buffer_get_string(&m, &len); 691 buffer_init(&cctx->cmd); 692 buffer_append(&cctx->cmd, cmd, strlen(cmd)); 693 694 env_len = buffer_get_int(&m); 695 env_len = MIN(env_len, 4096); 696 debug3("%s: receiving %d env vars", __func__, env_len); 697 if (env_len != 0) { 698 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1)); 699 for (i = 0; i < env_len; i++) 700 cctx->env[i] = buffer_get_string(&m, &len); 701 cctx->env[i] = NULL; 702 } 703 704 debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__, 705 cctx->want_tty, cctx->want_subsys, cmd); 706 707 /* Gather fds from client */ 708 new_fd[0] = mm_receive_fd(client_fd); 709 new_fd[1] = mm_receive_fd(client_fd); 710 new_fd[2] = mm_receive_fd(client_fd); 711 712 debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__, 713 new_fd[0], new_fd[1], new_fd[2]); 714 715 /* Try to pick up ttymodes from client before it goes raw */ 716 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1) 717 error("%s: tcgetattr: %s", __func__, strerror(errno)); 718 719 /* This roundtrip is just for synchronisation of ttymodes */ 720 buffer_clear(&m); 721 if (ssh_msg_send(client_fd, /* version */1, &m) == -1) { 722 error("%s: client msg_send failed", __func__); 723 close(client_fd); 724 close(new_fd[0]); 725 close(new_fd[1]); 726 close(new_fd[2]); 727 buffer_free(&m); 728 xfree(cctx->term); 729 if (env_len != 0) { 730 for (i = 0; i < env_len; i++) 731 xfree(cctx->env[i]); 732 xfree(cctx->env); 733 } 734 return; 735 } 736 buffer_free(&m); 737 738 /* enable nonblocking unless tty */ 739 if (!isatty(new_fd[0])) 740 set_nonblock(new_fd[0]); 741 if (!isatty(new_fd[1])) 742 set_nonblock(new_fd[1]); 743 if (!isatty(new_fd[2])) 744 set_nonblock(new_fd[2]); 745 746 set_nonblock(client_fd); 747 748 c = channel_new("session", SSH_CHANNEL_OPENING, 749 new_fd[0], new_fd[1], new_fd[2], 750 CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT, 751 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 752 753 /* XXX */ 754 c->ctl_fd = client_fd; 755 756 debug3("%s: channel_new: %d", __func__, c->self); 757 758 channel_send_open(c->self); 759 channel_register_confirm(c->self, client_extra_session2_setup, cctx); 760 } 761 762 static void 763 process_cmdline(void) 764 { 765 void (*handler)(int); 766 char *s, *cmd, *cancel_host; 767 int delete = 0; 768 int local = 0; 769 u_short cancel_port; 770 Forward fwd; 771 772 leave_raw_mode(); 773 handler = signal(SIGINT, SIG_IGN); 774 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 775 if (s == NULL) 776 goto out; 777 while (*s && isspace(*s)) 778 s++; 779 if (*s == '-') 780 s++; /* Skip cmdline '-', if any */ 781 if (*s == '\0') 782 goto out; 783 784 if (*s == 'h' || *s == 'H' || *s == '?') { 785 logit("Commands:"); 786 logit(" -Lport:host:hostport Request local forward"); 787 logit(" -Rport:host:hostport Request remote forward"); 788 logit(" -KRhostport Cancel remote forward"); 789 goto out; 790 } 791 792 if (*s == 'K') { 793 delete = 1; 794 s++; 795 } 796 if (*s != 'L' && *s != 'R') { 797 logit("Invalid command."); 798 goto out; 799 } 800 if (*s == 'L') 801 local = 1; 802 if (local && delete) { 803 logit("Not supported."); 804 goto out; 805 } 806 if ((!local || delete) && !compat20) { 807 logit("Not supported for SSH protocol version 1."); 808 goto out; 809 } 810 811 s++; 812 while (*s && isspace(*s)) 813 s++; 814 815 if (delete) { 816 cancel_port = 0; 817 cancel_host = hpdelim(&s); /* may be NULL */ 818 if (s != NULL) { 819 cancel_port = a2port(s); 820 cancel_host = cleanhostname(cancel_host); 821 } else { 822 cancel_port = a2port(cancel_host); 823 cancel_host = NULL; 824 } 825 if (cancel_port == 0) { 826 logit("Bad forwarding close port"); 827 goto out; 828 } 829 channel_request_rforward_cancel(cancel_host, cancel_port); 830 } else { 831 if (!parse_forward(&fwd, s)) { 832 logit("Bad forwarding specification."); 833 goto out; 834 } 835 if (local) { 836 if (channel_setup_local_fwd_listener(fwd.listen_host, 837 fwd.listen_port, fwd.connect_host, 838 fwd.connect_port, options.gateway_ports) < 0) { 839 logit("Port forwarding failed."); 840 goto out; 841 } 842 } else { 843 channel_request_remote_forwarding(fwd.listen_host, 844 fwd.listen_port, fwd.connect_host, 845 fwd.connect_port); 846 } 847 848 logit("Forwarding port."); 849 } 850 851 out: 852 signal(SIGINT, handler); 853 enter_raw_mode(); 854 if (cmd) 855 xfree(cmd); 856 } 857 858 /* process the characters one by one */ 859 static int 860 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) 861 { 862 char string[1024]; 863 pid_t pid; 864 int bytes = 0; 865 u_int i; 866 u_char ch; 867 char *s; 868 869 for (i = 0; i < len; i++) { 870 /* Get one character at a time. */ 871 ch = buf[i]; 872 873 if (escape_pending) { 874 /* We have previously seen an escape character. */ 875 /* Clear the flag now. */ 876 escape_pending = 0; 877 878 /* Process the escaped character. */ 879 switch (ch) { 880 case '.': 881 /* Terminate the connection. */ 882 snprintf(string, sizeof string, "%c.\r\n", escape_char); 883 buffer_append(berr, string, strlen(string)); 884 885 quit_pending = 1; 886 return -1; 887 888 case 'Z' - 64: 889 /* Suspend the program. */ 890 /* Print a message to that effect to the user. */ 891 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); 892 buffer_append(berr, string, strlen(string)); 893 894 /* Restore terminal modes and suspend. */ 895 client_suspend_self(bin, bout, berr); 896 897 /* We have been continued. */ 898 continue; 899 900 case 'B': 901 if (compat20) { 902 snprintf(string, sizeof string, 903 "%cB\r\n", escape_char); 904 buffer_append(berr, string, 905 strlen(string)); 906 channel_request_start(session_ident, 907 "break", 0); 908 packet_put_int(1000); 909 packet_send(); 910 } 911 continue; 912 913 case 'R': 914 if (compat20) { 915 if (datafellows & SSH_BUG_NOREKEY) 916 logit("Server does not support re-keying"); 917 else 918 need_rekeying = 1; 919 } 920 continue; 921 922 case '&': 923 /* 924 * Detach the program (continue to serve connections, 925 * but put in background and no more new connections). 926 */ 927 /* Restore tty modes. */ 928 leave_raw_mode(); 929 930 /* Stop listening for new connections. */ 931 channel_stop_listening(); 932 933 snprintf(string, sizeof string, 934 "%c& [backgrounded]\n", escape_char); 935 buffer_append(berr, string, strlen(string)); 936 937 /* Fork into background. */ 938 pid = fork(); 939 if (pid < 0) { 940 error("fork: %.100s", strerror(errno)); 941 continue; 942 } 943 if (pid != 0) { /* This is the parent. */ 944 /* The parent just exits. */ 945 exit(0); 946 } 947 /* The child continues serving connections. */ 948 if (compat20) { 949 buffer_append(bin, "\004", 1); 950 /* fake EOF on stdin */ 951 return -1; 952 } else if (!stdin_eof) { 953 /* 954 * Sending SSH_CMSG_EOF alone does not always appear 955 * to be enough. So we try to send an EOF character 956 * first. 957 */ 958 packet_start(SSH_CMSG_STDIN_DATA); 959 packet_put_string("\004", 1); 960 packet_send(); 961 /* Close stdin. */ 962 stdin_eof = 1; 963 if (buffer_len(bin) == 0) { 964 packet_start(SSH_CMSG_EOF); 965 packet_send(); 966 } 967 } 968 continue; 969 970 case '?': 971 snprintf(string, sizeof string, 972 "%c?\r\n\ 973 Supported escape sequences:\r\n\ 974 %c. - terminate connection\r\n\ 975 %cB - send a BREAK to the remote system\r\n\ 976 %cC - open a command line\r\n\ 977 %cR - Request rekey (SSH protocol 2 only)\r\n\ 978 %c^Z - suspend ssh\r\n\ 979 %c# - list forwarded connections\r\n\ 980 %c& - background ssh (when waiting for connections to terminate)\r\n\ 981 %c? - this message\r\n\ 982 %c%c - send the escape character by typing it twice\r\n\ 983 (Note that escapes are only recognized immediately after newline.)\r\n", 984 escape_char, escape_char, escape_char, escape_char, 985 escape_char, escape_char, escape_char, escape_char, 986 escape_char, escape_char, escape_char); 987 buffer_append(berr, string, strlen(string)); 988 continue; 989 990 case '#': 991 snprintf(string, sizeof string, "%c#\r\n", escape_char); 992 buffer_append(berr, string, strlen(string)); 993 s = channel_open_message(); 994 buffer_append(berr, s, strlen(s)); 995 xfree(s); 996 continue; 997 998 case 'C': 999 process_cmdline(); 1000 continue; 1001 1002 default: 1003 if (ch != escape_char) { 1004 buffer_put_char(bin, escape_char); 1005 bytes++; 1006 } 1007 /* Escaped characters fall through here */ 1008 break; 1009 } 1010 } else { 1011 /* 1012 * The previous character was not an escape char. Check if this 1013 * is an escape. 1014 */ 1015 if (last_was_cr && ch == escape_char) { 1016 /* It is. Set the flag and continue to next character. */ 1017 escape_pending = 1; 1018 continue; 1019 } 1020 } 1021 1022 /* 1023 * Normal character. Record whether it was a newline, 1024 * and append it to the buffer. 1025 */ 1026 last_was_cr = (ch == '\r' || ch == '\n'); 1027 buffer_put_char(bin, ch); 1028 bytes++; 1029 } 1030 return bytes; 1031 } 1032 1033 static void 1034 client_process_input(fd_set * readset) 1035 { 1036 int len; 1037 char buf[8192]; 1038 1039 /* Read input from stdin. */ 1040 if (FD_ISSET(fileno(stdin), readset)) { 1041 /* Read as much as possible. */ 1042 len = read(fileno(stdin), buf, sizeof(buf)); 1043 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 1044 return; /* we'll try again later */ 1045 if (len <= 0) { 1046 /* 1047 * Received EOF or error. They are treated 1048 * similarly, except that an error message is printed 1049 * if it was an error condition. 1050 */ 1051 if (len < 0) { 1052 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); 1053 buffer_append(&stderr_buffer, buf, strlen(buf)); 1054 } 1055 /* Mark that we have seen EOF. */ 1056 stdin_eof = 1; 1057 /* 1058 * Send an EOF message to the server unless there is 1059 * data in the buffer. If there is data in the 1060 * buffer, no message will be sent now. Code 1061 * elsewhere will send the EOF when the buffer 1062 * becomes empty if stdin_eof is set. 1063 */ 1064 if (buffer_len(&stdin_buffer) == 0) { 1065 packet_start(SSH_CMSG_EOF); 1066 packet_send(); 1067 } 1068 } else if (escape_char == SSH_ESCAPECHAR_NONE) { 1069 /* 1070 * Normal successful read, and no escape character. 1071 * Just append the data to buffer. 1072 */ 1073 buffer_append(&stdin_buffer, buf, len); 1074 } else { 1075 /* 1076 * Normal, successful read. But we have an escape character 1077 * and have to process the characters one by one. 1078 */ 1079 if (process_escapes(&stdin_buffer, &stdout_buffer, 1080 &stderr_buffer, buf, len) == -1) 1081 return; 1082 } 1083 } 1084 } 1085 1086 static void 1087 client_process_output(fd_set * writeset) 1088 { 1089 int len; 1090 char buf[100]; 1091 1092 /* Write buffered output to stdout. */ 1093 if (FD_ISSET(fileno(stdout), writeset)) { 1094 /* Write as much data as possible. */ 1095 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1096 buffer_len(&stdout_buffer)); 1097 if (len <= 0) { 1098 if (errno == EINTR || errno == EAGAIN) 1099 len = 0; 1100 else { 1101 /* 1102 * An error or EOF was encountered. Put an 1103 * error message to stderr buffer. 1104 */ 1105 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); 1106 buffer_append(&stderr_buffer, buf, strlen(buf)); 1107 quit_pending = 1; 1108 return; 1109 } 1110 } 1111 /* Consume printed data from the buffer. */ 1112 buffer_consume(&stdout_buffer, len); 1113 stdout_bytes += len; 1114 } 1115 /* Write buffered output to stderr. */ 1116 if (FD_ISSET(fileno(stderr), writeset)) { 1117 /* Write as much data as possible. */ 1118 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1119 buffer_len(&stderr_buffer)); 1120 if (len <= 0) { 1121 if (errno == EINTR || errno == EAGAIN) 1122 len = 0; 1123 else { 1124 /* EOF or error, but can't even print error message. */ 1125 quit_pending = 1; 1126 return; 1127 } 1128 } 1129 /* Consume printed characters from the buffer. */ 1130 buffer_consume(&stderr_buffer, len); 1131 stderr_bytes += len; 1132 } 1133 } 1134 1135 /* 1136 * Get packets from the connection input buffer, and process them as long as 1137 * there are packets available. 1138 * 1139 * Any unknown packets received during the actual 1140 * session cause the session to terminate. This is 1141 * intended to make debugging easier since no 1142 * confirmations are sent. Any compatible protocol 1143 * extensions must be negotiated during the 1144 * preparatory phase. 1145 */ 1146 1147 static void 1148 client_process_buffered_input_packets(void) 1149 { 1150 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL); 1151 } 1152 1153 /* scan buf[] for '~' before sending data to the peer */ 1154 1155 static int 1156 simple_escape_filter(Channel *c, char *buf, int len) 1157 { 1158 /* XXX we assume c->extended is writeable */ 1159 return process_escapes(&c->input, &c->output, &c->extended, buf, len); 1160 } 1161 1162 static void 1163 client_channel_closed(int id, void *arg) 1164 { 1165 channel_cancel_cleanup(id); 1166 session_closed = 1; 1167 leave_raw_mode(); 1168 } 1169 1170 /* 1171 * Implements the interactive session with the server. This is called after 1172 * the user has been authenticated, and a command has been started on the 1173 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1174 * used as an escape character for terminating or suspending the session. 1175 */ 1176 1177 int 1178 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1179 { 1180 fd_set *readset = NULL, *writeset = NULL; 1181 double start_time, total_time; 1182 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1183 u_int nalloc = 0; 1184 char buf[100]; 1185 1186 debug("Entering interactive session."); 1187 1188 start_time = get_current_time(); 1189 1190 /* Initialize variables. */ 1191 escape_pending = 0; 1192 last_was_cr = 1; 1193 exit_status = -1; 1194 stdin_eof = 0; 1195 buffer_high = 64 * 1024; 1196 connection_in = packet_get_connection_in(); 1197 connection_out = packet_get_connection_out(); 1198 max_fd = MAX(connection_in, connection_out); 1199 if (control_fd != -1) 1200 max_fd = MAX(max_fd, control_fd); 1201 1202 if (!compat20) { 1203 /* enable nonblocking unless tty */ 1204 if (!isatty(fileno(stdin))) 1205 set_nonblock(fileno(stdin)); 1206 if (!isatty(fileno(stdout))) 1207 set_nonblock(fileno(stdout)); 1208 if (!isatty(fileno(stderr))) 1209 set_nonblock(fileno(stderr)); 1210 max_fd = MAX(max_fd, fileno(stdin)); 1211 max_fd = MAX(max_fd, fileno(stdout)); 1212 max_fd = MAX(max_fd, fileno(stderr)); 1213 } 1214 stdin_bytes = 0; 1215 stdout_bytes = 0; 1216 stderr_bytes = 0; 1217 quit_pending = 0; 1218 escape_char = escape_char_arg; 1219 1220 /* Initialize buffers. */ 1221 buffer_init(&stdin_buffer); 1222 buffer_init(&stdout_buffer); 1223 buffer_init(&stderr_buffer); 1224 1225 client_init_dispatch(); 1226 1227 /* 1228 * Set signal handlers, (e.g. to restore non-blocking mode) 1229 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1230 */ 1231 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1232 signal(SIGHUP, signal_handler); 1233 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1234 signal(SIGINT, signal_handler); 1235 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1236 signal(SIGQUIT, signal_handler); 1237 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1238 signal(SIGTERM, signal_handler); 1239 signal(SIGWINCH, window_change_handler); 1240 1241 if (have_pty) 1242 enter_raw_mode(); 1243 1244 if (compat20) { 1245 session_ident = ssh2_chan_id; 1246 if (escape_char != SSH_ESCAPECHAR_NONE) 1247 channel_register_filter(session_ident, 1248 simple_escape_filter); 1249 if (session_ident != -1) 1250 channel_register_cleanup(session_ident, 1251 client_channel_closed); 1252 } else { 1253 /* Check if we should immediately send eof on stdin. */ 1254 client_check_initial_eof_on_stdin(); 1255 } 1256 1257 /* Main loop of the client for the interactive session mode. */ 1258 while (!quit_pending) { 1259 1260 /* Process buffered packets sent by the server. */ 1261 client_process_buffered_input_packets(); 1262 1263 if (compat20 && session_closed && !channel_still_open()) 1264 break; 1265 1266 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1267 1268 if (rekeying) { 1269 debug("rekeying in progress"); 1270 } else { 1271 /* 1272 * Make packets of buffered stdin data, and buffer 1273 * them for sending to the server. 1274 */ 1275 if (!compat20) 1276 client_make_packets_from_stdin_data(); 1277 1278 /* 1279 * Make packets from buffered channel data, and 1280 * enqueue them for sending to the server. 1281 */ 1282 if (packet_not_very_much_data_to_write()) 1283 channel_output_poll(); 1284 1285 /* 1286 * Check if the window size has changed, and buffer a 1287 * message about it to the server if so. 1288 */ 1289 client_check_window_change(); 1290 1291 if (quit_pending) 1292 break; 1293 } 1294 /* 1295 * Wait until we have something to do (something becomes 1296 * available on one of the descriptors). 1297 */ 1298 max_fd2 = max_fd; 1299 client_wait_until_can_do_something(&readset, &writeset, 1300 &max_fd2, &nalloc, rekeying); 1301 1302 if (quit_pending) 1303 break; 1304 1305 /* Do channel operations unless rekeying in progress. */ 1306 if (!rekeying) { 1307 channel_after_select(readset, writeset); 1308 if (need_rekeying || packet_need_rekeying()) { 1309 debug("need rekeying"); 1310 xxx_kex->done = 0; 1311 kex_send_kexinit(xxx_kex); 1312 need_rekeying = 0; 1313 } 1314 } 1315 1316 /* Buffer input from the connection. */ 1317 client_process_net_input(readset); 1318 1319 /* Accept control connections. */ 1320 client_process_control(readset); 1321 1322 if (quit_pending) 1323 break; 1324 1325 if (!compat20) { 1326 /* Buffer data from stdin */ 1327 client_process_input(readset); 1328 /* 1329 * Process output to stdout and stderr. Output to 1330 * the connection is processed elsewhere (above). 1331 */ 1332 client_process_output(writeset); 1333 } 1334 1335 /* Send as much buffered packet data as possible to the sender. */ 1336 if (FD_ISSET(connection_out, writeset)) 1337 packet_write_poll(); 1338 } 1339 if (readset) 1340 xfree(readset); 1341 if (writeset) 1342 xfree(writeset); 1343 1344 /* Terminate the session. */ 1345 1346 /* Stop watching for window change. */ 1347 signal(SIGWINCH, SIG_DFL); 1348 1349 channel_free_all(); 1350 1351 if (have_pty) 1352 leave_raw_mode(); 1353 1354 /* restore blocking io */ 1355 if (!isatty(fileno(stdin))) 1356 unset_nonblock(fileno(stdin)); 1357 if (!isatty(fileno(stdout))) 1358 unset_nonblock(fileno(stdout)); 1359 if (!isatty(fileno(stderr))) 1360 unset_nonblock(fileno(stderr)); 1361 1362 /* 1363 * If there was no shell or command requested, there will be no remote 1364 * exit status to be returned. In that case, clear error code if the 1365 * connection was deliberately terminated at this end. 1366 */ 1367 if (no_shell_flag && received_signal == SIGTERM) { 1368 received_signal = 0; 1369 exit_status = 0; 1370 } 1371 1372 if (received_signal) 1373 fatal("Killed by signal %d.", (int) received_signal); 1374 1375 /* 1376 * In interactive mode (with pseudo tty) display a message indicating 1377 * that the connection has been closed. 1378 */ 1379 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1380 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); 1381 buffer_append(&stderr_buffer, buf, strlen(buf)); 1382 } 1383 1384 /* Output any buffered data for stdout. */ 1385 while (buffer_len(&stdout_buffer) > 0) { 1386 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1387 buffer_len(&stdout_buffer)); 1388 if (len <= 0) { 1389 error("Write failed flushing stdout buffer."); 1390 break; 1391 } 1392 buffer_consume(&stdout_buffer, len); 1393 stdout_bytes += len; 1394 } 1395 1396 /* Output any buffered data for stderr. */ 1397 while (buffer_len(&stderr_buffer) > 0) { 1398 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1399 buffer_len(&stderr_buffer)); 1400 if (len <= 0) { 1401 error("Write failed flushing stderr buffer."); 1402 break; 1403 } 1404 buffer_consume(&stderr_buffer, len); 1405 stderr_bytes += len; 1406 } 1407 1408 /* Clear and free any buffers. */ 1409 memset(buf, 0, sizeof(buf)); 1410 buffer_free(&stdin_buffer); 1411 buffer_free(&stdout_buffer); 1412 buffer_free(&stderr_buffer); 1413 1414 /* Report bytes transferred, and transfer rates. */ 1415 total_time = get_current_time() - start_time; 1416 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", 1417 stdin_bytes, stdout_bytes, stderr_bytes, total_time); 1418 if (total_time > 0) 1419 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", 1420 stdin_bytes / total_time, stdout_bytes / total_time, 1421 stderr_bytes / total_time); 1422 1423 /* Return the exit status of the program. */ 1424 debug("Exit status %d", exit_status); 1425 return exit_status; 1426 } 1427 1428 /*********/ 1429 1430 static void 1431 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1432 { 1433 u_int data_len; 1434 char *data = packet_get_string(&data_len); 1435 packet_check_eom(); 1436 buffer_append(&stdout_buffer, data, data_len); 1437 memset(data, 0, data_len); 1438 xfree(data); 1439 } 1440 static void 1441 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1442 { 1443 u_int data_len; 1444 char *data = packet_get_string(&data_len); 1445 packet_check_eom(); 1446 buffer_append(&stderr_buffer, data, data_len); 1447 memset(data, 0, data_len); 1448 xfree(data); 1449 } 1450 static void 1451 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1452 { 1453 exit_status = packet_get_int(); 1454 packet_check_eom(); 1455 /* Acknowledge the exit. */ 1456 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1457 packet_send(); 1458 /* 1459 * Must wait for packet to be sent since we are 1460 * exiting the loop. 1461 */ 1462 packet_write_wait(); 1463 /* Flag that we want to exit. */ 1464 quit_pending = 1; 1465 } 1466 static void 1467 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1468 { 1469 Channel *c = NULL; 1470 int remote_id, sock; 1471 1472 /* Read the remote channel number from the message. */ 1473 remote_id = packet_get_int(); 1474 packet_check_eom(); 1475 1476 /* 1477 * Get a connection to the local authentication agent (this may again 1478 * get forwarded). 1479 */ 1480 sock = ssh_get_authentication_socket(); 1481 1482 /* 1483 * If we could not connect the agent, send an error message back to 1484 * the server. This should never happen unless the agent dies, 1485 * because authentication forwarding is only enabled if we have an 1486 * agent. 1487 */ 1488 if (sock >= 0) { 1489 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1490 -1, 0, 0, 0, "authentication agent connection", 1); 1491 c->remote_id = remote_id; 1492 c->force_drain = 1; 1493 } 1494 if (c == NULL) { 1495 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1496 packet_put_int(remote_id); 1497 } else { 1498 /* Send a confirmation to the remote host. */ 1499 debug("Forwarding authentication connection."); 1500 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1501 packet_put_int(remote_id); 1502 packet_put_int(c->self); 1503 } 1504 packet_send(); 1505 } 1506 1507 static Channel * 1508 client_request_forwarded_tcpip(const char *request_type, int rchan) 1509 { 1510 Channel *c = NULL; 1511 char *listen_address, *originator_address; 1512 int listen_port, originator_port; 1513 int sock; 1514 1515 /* Get rest of the packet */ 1516 listen_address = packet_get_string(NULL); 1517 listen_port = packet_get_int(); 1518 originator_address = packet_get_string(NULL); 1519 originator_port = packet_get_int(); 1520 packet_check_eom(); 1521 1522 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d", 1523 listen_address, listen_port, originator_address, originator_port); 1524 1525 sock = channel_connect_by_listen_address(listen_port); 1526 if (sock < 0) { 1527 xfree(originator_address); 1528 xfree(listen_address); 1529 return NULL; 1530 } 1531 c = channel_new("forwarded-tcpip", 1532 SSH_CHANNEL_CONNECTING, sock, sock, -1, 1533 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1534 originator_address, 1); 1535 xfree(originator_address); 1536 xfree(listen_address); 1537 return c; 1538 } 1539 1540 static Channel * 1541 client_request_x11(const char *request_type, int rchan) 1542 { 1543 Channel *c = NULL; 1544 char *originator; 1545 int originator_port; 1546 int sock; 1547 1548 if (!options.forward_x11) { 1549 error("Warning: ssh server tried X11 forwarding."); 1550 error("Warning: this is probably a break in attempt by a malicious server."); 1551 return NULL; 1552 } 1553 originator = packet_get_string(NULL); 1554 if (datafellows & SSH_BUG_X11FWD) { 1555 debug2("buggy server: x11 request w/o originator_port"); 1556 originator_port = 0; 1557 } else { 1558 originator_port = packet_get_int(); 1559 } 1560 packet_check_eom(); 1561 /* XXX check permission */ 1562 debug("client_request_x11: request from %s %d", originator, 1563 originator_port); 1564 xfree(originator); 1565 sock = x11_connect_display(); 1566 if (sock < 0) 1567 return NULL; 1568 c = channel_new("x11", 1569 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1570 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1571 c->force_drain = 1; 1572 return c; 1573 } 1574 1575 static Channel * 1576 client_request_agent(const char *request_type, int rchan) 1577 { 1578 Channel *c = NULL; 1579 int sock; 1580 1581 if (!options.forward_agent) { 1582 error("Warning: ssh server tried agent forwarding."); 1583 error("Warning: this is probably a break in attempt by a malicious server."); 1584 return NULL; 1585 } 1586 sock = ssh_get_authentication_socket(); 1587 if (sock < 0) 1588 return NULL; 1589 c = channel_new("authentication agent connection", 1590 SSH_CHANNEL_OPEN, sock, sock, -1, 1591 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1592 "authentication agent connection", 1); 1593 c->force_drain = 1; 1594 return c; 1595 } 1596 1597 /* XXXX move to generic input handler */ 1598 static void 1599 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1600 { 1601 Channel *c = NULL; 1602 char *ctype; 1603 int rchan; 1604 u_int rmaxpack, rwindow, len; 1605 1606 ctype = packet_get_string(&len); 1607 rchan = packet_get_int(); 1608 rwindow = packet_get_int(); 1609 rmaxpack = packet_get_int(); 1610 1611 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1612 ctype, rchan, rwindow, rmaxpack); 1613 1614 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1615 c = client_request_forwarded_tcpip(ctype, rchan); 1616 } else if (strcmp(ctype, "x11") == 0) { 1617 c = client_request_x11(ctype, rchan); 1618 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1619 c = client_request_agent(ctype, rchan); 1620 } 1621 /* XXX duplicate : */ 1622 if (c != NULL) { 1623 debug("confirm %s", ctype); 1624 c->remote_id = rchan; 1625 c->remote_window = rwindow; 1626 c->remote_maxpacket = rmaxpack; 1627 if (c->type != SSH_CHANNEL_CONNECTING) { 1628 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1629 packet_put_int(c->remote_id); 1630 packet_put_int(c->self); 1631 packet_put_int(c->local_window); 1632 packet_put_int(c->local_maxpacket); 1633 packet_send(); 1634 } 1635 } else { 1636 debug("failure %s", ctype); 1637 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1638 packet_put_int(rchan); 1639 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1640 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1641 packet_put_cstring("open failed"); 1642 packet_put_cstring(""); 1643 } 1644 packet_send(); 1645 } 1646 xfree(ctype); 1647 } 1648 static void 1649 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1650 { 1651 Channel *c = NULL; 1652 int exitval, id, reply, success = 0; 1653 char *rtype; 1654 1655 id = packet_get_int(); 1656 rtype = packet_get_string(NULL); 1657 reply = packet_get_char(); 1658 1659 debug("client_input_channel_req: channel %d rtype %s reply %d", 1660 id, rtype, reply); 1661 1662 if (id == -1) { 1663 error("client_input_channel_req: request for channel -1"); 1664 } else if ((c = channel_lookup(id)) == NULL) { 1665 error("client_input_channel_req: channel %d: unknown channel", id); 1666 } else if (strcmp(rtype, "exit-status") == 0) { 1667 exitval = packet_get_int(); 1668 if (id == session_ident) { 1669 success = 1; 1670 exit_status = exitval; 1671 } else if (c->ctl_fd == -1) { 1672 error("client_input_channel_req: unexpected channel %d", 1673 session_ident); 1674 } else { 1675 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1676 success = 1; 1677 } 1678 packet_check_eom(); 1679 } 1680 if (reply) { 1681 packet_start(success ? 1682 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1683 packet_put_int(id); 1684 packet_send(); 1685 } 1686 xfree(rtype); 1687 } 1688 static void 1689 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1690 { 1691 char *rtype; 1692 int want_reply; 1693 int success = 0; 1694 1695 rtype = packet_get_string(NULL); 1696 want_reply = packet_get_char(); 1697 debug("client_input_global_request: rtype %s want_reply %d", 1698 rtype, want_reply); 1699 if (want_reply) { 1700 packet_start(success ? 1701 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1702 packet_send(); 1703 packet_write_wait(); 1704 } 1705 xfree(rtype); 1706 } 1707 1708 void 1709 client_session2_setup(int id, int want_tty, int want_subsystem, 1710 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env, 1711 dispatch_fn *subsys_repl) 1712 { 1713 int len; 1714 Channel *c = NULL; 1715 1716 debug2("%s: id %d", __func__, id); 1717 1718 if ((c = channel_lookup(id)) == NULL) 1719 fatal("client_session2_setup: channel %d: unknown channel", id); 1720 1721 if (want_tty) { 1722 struct winsize ws; 1723 struct termios tio; 1724 1725 /* Store window size in the packet. */ 1726 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1727 memset(&ws, 0, sizeof(ws)); 1728 1729 channel_request_start(id, "pty-req", 0); 1730 packet_put_cstring(term != NULL ? term : ""); 1731 packet_put_int(ws.ws_col); 1732 packet_put_int(ws.ws_row); 1733 packet_put_int(ws.ws_xpixel); 1734 packet_put_int(ws.ws_ypixel); 1735 tio = get_saved_tio(); 1736 tty_make_modes(-1, tiop != NULL ? tiop : &tio); 1737 packet_send(); 1738 /* XXX wait for reply */ 1739 c->client_tty = 1; 1740 } 1741 1742 /* Transfer any environment variables from client to server */ 1743 if (options.num_send_env != 0 && env != NULL) { 1744 int i, j, matched; 1745 char *name, *val; 1746 1747 debug("Sending environment."); 1748 for (i = 0; env[i] != NULL; i++) { 1749 /* Split */ 1750 name = xstrdup(env[i]); 1751 if ((val = strchr(name, '=')) == NULL) { 1752 free(name); 1753 continue; 1754 } 1755 *val++ = '\0'; 1756 1757 matched = 0; 1758 for (j = 0; j < options.num_send_env; j++) { 1759 if (match_pattern(name, options.send_env[j])) { 1760 matched = 1; 1761 break; 1762 } 1763 } 1764 if (!matched) { 1765 debug3("Ignored env %s", name); 1766 free(name); 1767 continue; 1768 } 1769 1770 debug("Sending env %s = %s", name, val); 1771 channel_request_start(id, "env", 0); 1772 packet_put_cstring(name); 1773 packet_put_cstring(val); 1774 packet_send(); 1775 free(name); 1776 } 1777 } 1778 1779 len = buffer_len(cmd); 1780 if (len > 0) { 1781 if (len > 900) 1782 len = 900; 1783 if (want_subsystem) { 1784 debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd)); 1785 channel_request_start(id, "subsystem", subsys_repl != NULL); 1786 if (subsys_repl != NULL) { 1787 /* register callback for reply */ 1788 /* XXX we assume that client_loop has already been called */ 1789 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl); 1790 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl); 1791 } 1792 } else { 1793 debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd)); 1794 channel_request_start(id, "exec", 0); 1795 } 1796 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1797 packet_send(); 1798 } else { 1799 channel_request_start(id, "shell", 0); 1800 packet_send(); 1801 } 1802 } 1803 1804 static void 1805 client_init_dispatch_20(void) 1806 { 1807 dispatch_init(&dispatch_protocol_error); 1808 1809 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1810 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1811 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1812 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1813 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1814 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1815 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1816 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1817 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1818 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1819 1820 /* rekeying */ 1821 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1822 1823 /* global request reply messages */ 1824 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 1825 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 1826 } 1827 static void 1828 client_init_dispatch_13(void) 1829 { 1830 dispatch_init(NULL); 1831 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 1832 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 1833 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 1834 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1835 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1836 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 1837 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 1838 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 1839 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 1840 1841 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 1842 &client_input_agent_open : &deny_input_open); 1843 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 1844 &x11_input_open : &deny_input_open); 1845 } 1846 static void 1847 client_init_dispatch_15(void) 1848 { 1849 client_init_dispatch_13(); 1850 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 1851 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 1852 } 1853 static void 1854 client_init_dispatch(void) 1855 { 1856 if (compat20) 1857 client_init_dispatch_20(); 1858 else if (compat13) 1859 client_init_dispatch_13(); 1860 else 1861 client_init_dispatch_15(); 1862 } 1863 1864 /* client specific fatal cleanup */ 1865 void 1866 cleanup_exit(int i) 1867 { 1868 leave_raw_mode(); 1869 leave_non_blocking(); 1870 if (options.control_path != NULL && control_fd != -1) 1871 unlink(options.control_path); 1872 _exit(i); 1873 } 1874