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 1.134 2004/11/07 00:01:46 djm 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; 767 u_short fwd_port, fwd_host_port; 768 char buf[1024], sfwd_port[6], sfwd_host_port[6]; 769 int delete = 0; 770 int local = 0; 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 if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) { 817 logit("Bad forwarding specification."); 818 goto out; 819 } 820 if ((fwd_host_port = a2port(sfwd_host_port)) == 0) { 821 logit("Bad forwarding port(s)."); 822 goto out; 823 } 824 channel_request_rforward_cancel(fwd_host_port); 825 } else { 826 if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]", 827 sfwd_port, buf, sfwd_host_port) != 3 && 828 sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]", 829 sfwd_port, buf, sfwd_host_port) != 3) { 830 logit("Bad forwarding specification."); 831 goto out; 832 } 833 if ((fwd_port = a2port(sfwd_port)) == 0 || 834 (fwd_host_port = a2port(sfwd_host_port)) == 0) { 835 logit("Bad forwarding port(s)."); 836 goto out; 837 } 838 if (local) { 839 if (channel_setup_local_fwd_listener(fwd_port, buf, 840 fwd_host_port, options.gateway_ports) < 0) { 841 logit("Port forwarding failed."); 842 goto out; 843 } 844 } else 845 channel_request_remote_forwarding(fwd_port, buf, 846 fwd_host_port); 847 logit("Forwarding port."); 848 } 849 850 out: 851 signal(SIGINT, handler); 852 enter_raw_mode(); 853 if (cmd) 854 xfree(cmd); 855 } 856 857 /* process the characters one by one */ 858 static int 859 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) 860 { 861 char string[1024]; 862 pid_t pid; 863 int bytes = 0; 864 u_int i; 865 u_char ch; 866 char *s; 867 868 for (i = 0; i < len; i++) { 869 /* Get one character at a time. */ 870 ch = buf[i]; 871 872 if (escape_pending) { 873 /* We have previously seen an escape character. */ 874 /* Clear the flag now. */ 875 escape_pending = 0; 876 877 /* Process the escaped character. */ 878 switch (ch) { 879 case '.': 880 /* Terminate the connection. */ 881 snprintf(string, sizeof string, "%c.\r\n", escape_char); 882 buffer_append(berr, string, strlen(string)); 883 884 quit_pending = 1; 885 return -1; 886 887 case 'Z' - 64: 888 /* Suspend the program. */ 889 /* Print a message to that effect to the user. */ 890 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); 891 buffer_append(berr, string, strlen(string)); 892 893 /* Restore terminal modes and suspend. */ 894 client_suspend_self(bin, bout, berr); 895 896 /* We have been continued. */ 897 continue; 898 899 case 'B': 900 if (compat20) { 901 snprintf(string, sizeof string, 902 "%cB\r\n", escape_char); 903 buffer_append(berr, string, 904 strlen(string)); 905 channel_request_start(session_ident, 906 "break", 0); 907 packet_put_int(1000); 908 packet_send(); 909 } 910 continue; 911 912 case 'R': 913 if (compat20) { 914 if (datafellows & SSH_BUG_NOREKEY) 915 logit("Server does not support re-keying"); 916 else 917 need_rekeying = 1; 918 } 919 continue; 920 921 case '&': 922 /* 923 * Detach the program (continue to serve connections, 924 * but put in background and no more new connections). 925 */ 926 /* Restore tty modes. */ 927 leave_raw_mode(); 928 929 /* Stop listening for new connections. */ 930 channel_stop_listening(); 931 932 snprintf(string, sizeof string, 933 "%c& [backgrounded]\n", escape_char); 934 buffer_append(berr, string, strlen(string)); 935 936 /* Fork into background. */ 937 pid = fork(); 938 if (pid < 0) { 939 error("fork: %.100s", strerror(errno)); 940 continue; 941 } 942 if (pid != 0) { /* This is the parent. */ 943 /* The parent just exits. */ 944 exit(0); 945 } 946 /* The child continues serving connections. */ 947 if (compat20) { 948 buffer_append(bin, "\004", 1); 949 /* fake EOF on stdin */ 950 return -1; 951 } else if (!stdin_eof) { 952 /* 953 * Sending SSH_CMSG_EOF alone does not always appear 954 * to be enough. So we try to send an EOF character 955 * first. 956 */ 957 packet_start(SSH_CMSG_STDIN_DATA); 958 packet_put_string("\004", 1); 959 packet_send(); 960 /* Close stdin. */ 961 stdin_eof = 1; 962 if (buffer_len(bin) == 0) { 963 packet_start(SSH_CMSG_EOF); 964 packet_send(); 965 } 966 } 967 continue; 968 969 case '?': 970 snprintf(string, sizeof string, 971 "%c?\r\n\ 972 Supported escape sequences:\r\n\ 973 %c. - terminate connection\r\n\ 974 %cB - send a BREAK to the remote system\r\n\ 975 %cC - open a command line\r\n\ 976 %cR - Request rekey (SSH protocol 2 only)\r\n\ 977 %c^Z - suspend ssh\r\n\ 978 %c# - list forwarded connections\r\n\ 979 %c& - background ssh (when waiting for connections to terminate)\r\n\ 980 %c? - this message\r\n\ 981 %c%c - send the escape character by typing it twice\r\n\ 982 (Note that escapes are only recognized immediately after newline.)\r\n", 983 escape_char, escape_char, escape_char, escape_char, 984 escape_char, escape_char, escape_char, escape_char, 985 escape_char, escape_char, escape_char); 986 buffer_append(berr, string, strlen(string)); 987 continue; 988 989 case '#': 990 snprintf(string, sizeof string, "%c#\r\n", escape_char); 991 buffer_append(berr, string, strlen(string)); 992 s = channel_open_message(); 993 buffer_append(berr, s, strlen(s)); 994 xfree(s); 995 continue; 996 997 case 'C': 998 process_cmdline(); 999 continue; 1000 1001 default: 1002 if (ch != escape_char) { 1003 buffer_put_char(bin, escape_char); 1004 bytes++; 1005 } 1006 /* Escaped characters fall through here */ 1007 break; 1008 } 1009 } else { 1010 /* 1011 * The previous character was not an escape char. Check if this 1012 * is an escape. 1013 */ 1014 if (last_was_cr && ch == escape_char) { 1015 /* It is. Set the flag and continue to next character. */ 1016 escape_pending = 1; 1017 continue; 1018 } 1019 } 1020 1021 /* 1022 * Normal character. Record whether it was a newline, 1023 * and append it to the buffer. 1024 */ 1025 last_was_cr = (ch == '\r' || ch == '\n'); 1026 buffer_put_char(bin, ch); 1027 bytes++; 1028 } 1029 return bytes; 1030 } 1031 1032 static void 1033 client_process_input(fd_set * readset) 1034 { 1035 int len; 1036 char buf[8192]; 1037 1038 /* Read input from stdin. */ 1039 if (FD_ISSET(fileno(stdin), readset)) { 1040 /* Read as much as possible. */ 1041 len = read(fileno(stdin), buf, sizeof(buf)); 1042 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 1043 return; /* we'll try again later */ 1044 if (len <= 0) { 1045 /* 1046 * Received EOF or error. They are treated 1047 * similarly, except that an error message is printed 1048 * if it was an error condition. 1049 */ 1050 if (len < 0) { 1051 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); 1052 buffer_append(&stderr_buffer, buf, strlen(buf)); 1053 } 1054 /* Mark that we have seen EOF. */ 1055 stdin_eof = 1; 1056 /* 1057 * Send an EOF message to the server unless there is 1058 * data in the buffer. If there is data in the 1059 * buffer, no message will be sent now. Code 1060 * elsewhere will send the EOF when the buffer 1061 * becomes empty if stdin_eof is set. 1062 */ 1063 if (buffer_len(&stdin_buffer) == 0) { 1064 packet_start(SSH_CMSG_EOF); 1065 packet_send(); 1066 } 1067 } else if (escape_char == SSH_ESCAPECHAR_NONE) { 1068 /* 1069 * Normal successful read, and no escape character. 1070 * Just append the data to buffer. 1071 */ 1072 buffer_append(&stdin_buffer, buf, len); 1073 } else { 1074 /* 1075 * Normal, successful read. But we have an escape character 1076 * and have to process the characters one by one. 1077 */ 1078 if (process_escapes(&stdin_buffer, &stdout_buffer, 1079 &stderr_buffer, buf, len) == -1) 1080 return; 1081 } 1082 } 1083 } 1084 1085 static void 1086 client_process_output(fd_set * writeset) 1087 { 1088 int len; 1089 char buf[100]; 1090 1091 /* Write buffered output to stdout. */ 1092 if (FD_ISSET(fileno(stdout), writeset)) { 1093 /* Write as much data as possible. */ 1094 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1095 buffer_len(&stdout_buffer)); 1096 if (len <= 0) { 1097 if (errno == EINTR || errno == EAGAIN) 1098 len = 0; 1099 else { 1100 /* 1101 * An error or EOF was encountered. Put an 1102 * error message to stderr buffer. 1103 */ 1104 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); 1105 buffer_append(&stderr_buffer, buf, strlen(buf)); 1106 quit_pending = 1; 1107 return; 1108 } 1109 } 1110 /* Consume printed data from the buffer. */ 1111 buffer_consume(&stdout_buffer, len); 1112 stdout_bytes += len; 1113 } 1114 /* Write buffered output to stderr. */ 1115 if (FD_ISSET(fileno(stderr), writeset)) { 1116 /* Write as much data as possible. */ 1117 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1118 buffer_len(&stderr_buffer)); 1119 if (len <= 0) { 1120 if (errno == EINTR || errno == EAGAIN) 1121 len = 0; 1122 else { 1123 /* EOF or error, but can't even print error message. */ 1124 quit_pending = 1; 1125 return; 1126 } 1127 } 1128 /* Consume printed characters from the buffer. */ 1129 buffer_consume(&stderr_buffer, len); 1130 stderr_bytes += len; 1131 } 1132 } 1133 1134 /* 1135 * Get packets from the connection input buffer, and process them as long as 1136 * there are packets available. 1137 * 1138 * Any unknown packets received during the actual 1139 * session cause the session to terminate. This is 1140 * intended to make debugging easier since no 1141 * confirmations are sent. Any compatible protocol 1142 * extensions must be negotiated during the 1143 * preparatory phase. 1144 */ 1145 1146 static void 1147 client_process_buffered_input_packets(void) 1148 { 1149 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL); 1150 } 1151 1152 /* scan buf[] for '~' before sending data to the peer */ 1153 1154 static int 1155 simple_escape_filter(Channel *c, char *buf, int len) 1156 { 1157 /* XXX we assume c->extended is writeable */ 1158 return process_escapes(&c->input, &c->output, &c->extended, buf, len); 1159 } 1160 1161 static void 1162 client_channel_closed(int id, void *arg) 1163 { 1164 channel_cancel_cleanup(id); 1165 session_closed = 1; 1166 leave_raw_mode(); 1167 } 1168 1169 /* 1170 * Implements the interactive session with the server. This is called after 1171 * the user has been authenticated, and a command has been started on the 1172 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1173 * used as an escape character for terminating or suspending the session. 1174 */ 1175 1176 int 1177 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1178 { 1179 fd_set *readset = NULL, *writeset = NULL; 1180 double start_time, total_time; 1181 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1182 u_int nalloc = 0; 1183 char buf[100]; 1184 1185 debug("Entering interactive session."); 1186 1187 start_time = get_current_time(); 1188 1189 /* Initialize variables. */ 1190 escape_pending = 0; 1191 last_was_cr = 1; 1192 exit_status = -1; 1193 stdin_eof = 0; 1194 buffer_high = 64 * 1024; 1195 connection_in = packet_get_connection_in(); 1196 connection_out = packet_get_connection_out(); 1197 max_fd = MAX(connection_in, connection_out); 1198 if (control_fd != -1) 1199 max_fd = MAX(max_fd, control_fd); 1200 1201 if (!compat20) { 1202 /* enable nonblocking unless tty */ 1203 if (!isatty(fileno(stdin))) 1204 set_nonblock(fileno(stdin)); 1205 if (!isatty(fileno(stdout))) 1206 set_nonblock(fileno(stdout)); 1207 if (!isatty(fileno(stderr))) 1208 set_nonblock(fileno(stderr)); 1209 max_fd = MAX(max_fd, fileno(stdin)); 1210 max_fd = MAX(max_fd, fileno(stdout)); 1211 max_fd = MAX(max_fd, fileno(stderr)); 1212 } 1213 stdin_bytes = 0; 1214 stdout_bytes = 0; 1215 stderr_bytes = 0; 1216 quit_pending = 0; 1217 escape_char = escape_char_arg; 1218 1219 /* Initialize buffers. */ 1220 buffer_init(&stdin_buffer); 1221 buffer_init(&stdout_buffer); 1222 buffer_init(&stderr_buffer); 1223 1224 client_init_dispatch(); 1225 1226 /* 1227 * Set signal handlers, (e.g. to restore non-blocking mode) 1228 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1229 */ 1230 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1231 signal(SIGHUP, signal_handler); 1232 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1233 signal(SIGINT, signal_handler); 1234 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1235 signal(SIGQUIT, signal_handler); 1236 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1237 signal(SIGTERM, signal_handler); 1238 signal(SIGWINCH, window_change_handler); 1239 1240 if (have_pty) 1241 enter_raw_mode(); 1242 1243 if (compat20) { 1244 session_ident = ssh2_chan_id; 1245 if (escape_char != SSH_ESCAPECHAR_NONE) 1246 channel_register_filter(session_ident, 1247 simple_escape_filter); 1248 if (session_ident != -1) 1249 channel_register_cleanup(session_ident, 1250 client_channel_closed); 1251 } else { 1252 /* Check if we should immediately send eof on stdin. */ 1253 client_check_initial_eof_on_stdin(); 1254 } 1255 1256 /* Main loop of the client for the interactive session mode. */ 1257 while (!quit_pending) { 1258 1259 /* Process buffered packets sent by the server. */ 1260 client_process_buffered_input_packets(); 1261 1262 if (compat20 && session_closed && !channel_still_open()) 1263 break; 1264 1265 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1266 1267 if (rekeying) { 1268 debug("rekeying in progress"); 1269 } else { 1270 /* 1271 * Make packets of buffered stdin data, and buffer 1272 * them for sending to the server. 1273 */ 1274 if (!compat20) 1275 client_make_packets_from_stdin_data(); 1276 1277 /* 1278 * Make packets from buffered channel data, and 1279 * enqueue them for sending to the server. 1280 */ 1281 if (packet_not_very_much_data_to_write()) 1282 channel_output_poll(); 1283 1284 /* 1285 * Check if the window size has changed, and buffer a 1286 * message about it to the server if so. 1287 */ 1288 client_check_window_change(); 1289 1290 if (quit_pending) 1291 break; 1292 } 1293 /* 1294 * Wait until we have something to do (something becomes 1295 * available on one of the descriptors). 1296 */ 1297 max_fd2 = max_fd; 1298 client_wait_until_can_do_something(&readset, &writeset, 1299 &max_fd2, &nalloc, rekeying); 1300 1301 if (quit_pending) 1302 break; 1303 1304 /* Do channel operations unless rekeying in progress. */ 1305 if (!rekeying) { 1306 channel_after_select(readset, writeset); 1307 if (need_rekeying || packet_need_rekeying()) { 1308 debug("need rekeying"); 1309 xxx_kex->done = 0; 1310 kex_send_kexinit(xxx_kex); 1311 need_rekeying = 0; 1312 } 1313 } 1314 1315 /* Buffer input from the connection. */ 1316 client_process_net_input(readset); 1317 1318 /* Accept control connections. */ 1319 client_process_control(readset); 1320 1321 if (quit_pending) 1322 break; 1323 1324 if (!compat20) { 1325 /* Buffer data from stdin */ 1326 client_process_input(readset); 1327 /* 1328 * Process output to stdout and stderr. Output to 1329 * the connection is processed elsewhere (above). 1330 */ 1331 client_process_output(writeset); 1332 } 1333 1334 /* Send as much buffered packet data as possible to the sender. */ 1335 if (FD_ISSET(connection_out, writeset)) 1336 packet_write_poll(); 1337 } 1338 if (readset) 1339 xfree(readset); 1340 if (writeset) 1341 xfree(writeset); 1342 1343 /* Terminate the session. */ 1344 1345 /* Stop watching for window change. */ 1346 signal(SIGWINCH, SIG_DFL); 1347 1348 channel_free_all(); 1349 1350 if (have_pty) 1351 leave_raw_mode(); 1352 1353 /* restore blocking io */ 1354 if (!isatty(fileno(stdin))) 1355 unset_nonblock(fileno(stdin)); 1356 if (!isatty(fileno(stdout))) 1357 unset_nonblock(fileno(stdout)); 1358 if (!isatty(fileno(stderr))) 1359 unset_nonblock(fileno(stderr)); 1360 1361 /* 1362 * If there was no shell or command requested, there will be no remote 1363 * exit status to be returned. In that case, clear error code if the 1364 * connection was deliberately terminated at this end. 1365 */ 1366 if (no_shell_flag && received_signal == SIGTERM) { 1367 received_signal = 0; 1368 exit_status = 0; 1369 } 1370 1371 if (received_signal) 1372 fatal("Killed by signal %d.", (int) received_signal); 1373 1374 /* 1375 * In interactive mode (with pseudo tty) display a message indicating 1376 * that the connection has been closed. 1377 */ 1378 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1379 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); 1380 buffer_append(&stderr_buffer, buf, strlen(buf)); 1381 } 1382 1383 /* Output any buffered data for stdout. */ 1384 while (buffer_len(&stdout_buffer) > 0) { 1385 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1386 buffer_len(&stdout_buffer)); 1387 if (len <= 0) { 1388 error("Write failed flushing stdout buffer."); 1389 break; 1390 } 1391 buffer_consume(&stdout_buffer, len); 1392 stdout_bytes += len; 1393 } 1394 1395 /* Output any buffered data for stderr. */ 1396 while (buffer_len(&stderr_buffer) > 0) { 1397 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1398 buffer_len(&stderr_buffer)); 1399 if (len <= 0) { 1400 error("Write failed flushing stderr buffer."); 1401 break; 1402 } 1403 buffer_consume(&stderr_buffer, len); 1404 stderr_bytes += len; 1405 } 1406 1407 /* Clear and free any buffers. */ 1408 memset(buf, 0, sizeof(buf)); 1409 buffer_free(&stdin_buffer); 1410 buffer_free(&stdout_buffer); 1411 buffer_free(&stderr_buffer); 1412 1413 /* Report bytes transferred, and transfer rates. */ 1414 total_time = get_current_time() - start_time; 1415 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", 1416 stdin_bytes, stdout_bytes, stderr_bytes, total_time); 1417 if (total_time > 0) 1418 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", 1419 stdin_bytes / total_time, stdout_bytes / total_time, 1420 stderr_bytes / total_time); 1421 1422 /* Return the exit status of the program. */ 1423 debug("Exit status %d", exit_status); 1424 return exit_status; 1425 } 1426 1427 /*********/ 1428 1429 static void 1430 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1431 { 1432 u_int data_len; 1433 char *data = packet_get_string(&data_len); 1434 packet_check_eom(); 1435 buffer_append(&stdout_buffer, data, data_len); 1436 memset(data, 0, data_len); 1437 xfree(data); 1438 } 1439 static void 1440 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1441 { 1442 u_int data_len; 1443 char *data = packet_get_string(&data_len); 1444 packet_check_eom(); 1445 buffer_append(&stderr_buffer, data, data_len); 1446 memset(data, 0, data_len); 1447 xfree(data); 1448 } 1449 static void 1450 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1451 { 1452 exit_status = packet_get_int(); 1453 packet_check_eom(); 1454 /* Acknowledge the exit. */ 1455 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1456 packet_send(); 1457 /* 1458 * Must wait for packet to be sent since we are 1459 * exiting the loop. 1460 */ 1461 packet_write_wait(); 1462 /* Flag that we want to exit. */ 1463 quit_pending = 1; 1464 } 1465 static void 1466 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1467 { 1468 Channel *c = NULL; 1469 int remote_id, sock; 1470 1471 /* Read the remote channel number from the message. */ 1472 remote_id = packet_get_int(); 1473 packet_check_eom(); 1474 1475 /* 1476 * Get a connection to the local authentication agent (this may again 1477 * get forwarded). 1478 */ 1479 sock = ssh_get_authentication_socket(); 1480 1481 /* 1482 * If we could not connect the agent, send an error message back to 1483 * the server. This should never happen unless the agent dies, 1484 * because authentication forwarding is only enabled if we have an 1485 * agent. 1486 */ 1487 if (sock >= 0) { 1488 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1489 -1, 0, 0, 0, "authentication agent connection", 1); 1490 c->remote_id = remote_id; 1491 c->force_drain = 1; 1492 } 1493 if (c == NULL) { 1494 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1495 packet_put_int(remote_id); 1496 } else { 1497 /* Send a confirmation to the remote host. */ 1498 debug("Forwarding authentication connection."); 1499 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1500 packet_put_int(remote_id); 1501 packet_put_int(c->self); 1502 } 1503 packet_send(); 1504 } 1505 1506 static Channel * 1507 client_request_forwarded_tcpip(const char *request_type, int rchan) 1508 { 1509 Channel *c = NULL; 1510 char *listen_address, *originator_address; 1511 int listen_port, originator_port; 1512 int sock; 1513 1514 /* Get rest of the packet */ 1515 listen_address = packet_get_string(NULL); 1516 listen_port = packet_get_int(); 1517 originator_address = packet_get_string(NULL); 1518 originator_port = packet_get_int(); 1519 packet_check_eom(); 1520 1521 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d", 1522 listen_address, listen_port, originator_address, originator_port); 1523 1524 sock = channel_connect_by_listen_address(listen_port); 1525 if (sock < 0) { 1526 xfree(originator_address); 1527 xfree(listen_address); 1528 return NULL; 1529 } 1530 c = channel_new("forwarded-tcpip", 1531 SSH_CHANNEL_CONNECTING, sock, sock, -1, 1532 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1533 originator_address, 1); 1534 xfree(originator_address); 1535 xfree(listen_address); 1536 return c; 1537 } 1538 1539 static Channel * 1540 client_request_x11(const char *request_type, int rchan) 1541 { 1542 Channel *c = NULL; 1543 char *originator; 1544 int originator_port; 1545 int sock; 1546 1547 if (!options.forward_x11) { 1548 error("Warning: ssh server tried X11 forwarding."); 1549 error("Warning: this is probably a break in attempt by a malicious server."); 1550 return NULL; 1551 } 1552 originator = packet_get_string(NULL); 1553 if (datafellows & SSH_BUG_X11FWD) { 1554 debug2("buggy server: x11 request w/o originator_port"); 1555 originator_port = 0; 1556 } else { 1557 originator_port = packet_get_int(); 1558 } 1559 packet_check_eom(); 1560 /* XXX check permission */ 1561 debug("client_request_x11: request from %s %d", originator, 1562 originator_port); 1563 xfree(originator); 1564 sock = x11_connect_display(); 1565 if (sock < 0) 1566 return NULL; 1567 c = channel_new("x11", 1568 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1569 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1570 c->force_drain = 1; 1571 return c; 1572 } 1573 1574 static Channel * 1575 client_request_agent(const char *request_type, int rchan) 1576 { 1577 Channel *c = NULL; 1578 int sock; 1579 1580 if (!options.forward_agent) { 1581 error("Warning: ssh server tried agent forwarding."); 1582 error("Warning: this is probably a break in attempt by a malicious server."); 1583 return NULL; 1584 } 1585 sock = ssh_get_authentication_socket(); 1586 if (sock < 0) 1587 return NULL; 1588 c = channel_new("authentication agent connection", 1589 SSH_CHANNEL_OPEN, sock, sock, -1, 1590 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, 1591 "authentication agent connection", 1); 1592 c->force_drain = 1; 1593 return c; 1594 } 1595 1596 /* XXXX move to generic input handler */ 1597 static void 1598 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1599 { 1600 Channel *c = NULL; 1601 char *ctype; 1602 int rchan; 1603 u_int rmaxpack, rwindow, len; 1604 1605 ctype = packet_get_string(&len); 1606 rchan = packet_get_int(); 1607 rwindow = packet_get_int(); 1608 rmaxpack = packet_get_int(); 1609 1610 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1611 ctype, rchan, rwindow, rmaxpack); 1612 1613 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1614 c = client_request_forwarded_tcpip(ctype, rchan); 1615 } else if (strcmp(ctype, "x11") == 0) { 1616 c = client_request_x11(ctype, rchan); 1617 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1618 c = client_request_agent(ctype, rchan); 1619 } 1620 /* XXX duplicate : */ 1621 if (c != NULL) { 1622 debug("confirm %s", ctype); 1623 c->remote_id = rchan; 1624 c->remote_window = rwindow; 1625 c->remote_maxpacket = rmaxpack; 1626 if (c->type != SSH_CHANNEL_CONNECTING) { 1627 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1628 packet_put_int(c->remote_id); 1629 packet_put_int(c->self); 1630 packet_put_int(c->local_window); 1631 packet_put_int(c->local_maxpacket); 1632 packet_send(); 1633 } 1634 } else { 1635 debug("failure %s", ctype); 1636 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1637 packet_put_int(rchan); 1638 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1639 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1640 packet_put_cstring("open failed"); 1641 packet_put_cstring(""); 1642 } 1643 packet_send(); 1644 } 1645 xfree(ctype); 1646 } 1647 static void 1648 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1649 { 1650 Channel *c = NULL; 1651 int exitval, id, reply, success = 0; 1652 char *rtype; 1653 1654 id = packet_get_int(); 1655 rtype = packet_get_string(NULL); 1656 reply = packet_get_char(); 1657 1658 debug("client_input_channel_req: channel %d rtype %s reply %d", 1659 id, rtype, reply); 1660 1661 if (id == -1) { 1662 error("client_input_channel_req: request for channel -1"); 1663 } else if ((c = channel_lookup(id)) == NULL) { 1664 error("client_input_channel_req: channel %d: unknown channel", id); 1665 } else if (strcmp(rtype, "exit-status") == 0) { 1666 exitval = packet_get_int(); 1667 if (id == session_ident) { 1668 success = 1; 1669 exit_status = exitval; 1670 } else if (c->ctl_fd == -1) { 1671 error("client_input_channel_req: unexpected channel %d", 1672 session_ident); 1673 } else { 1674 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1675 success = 1; 1676 } 1677 packet_check_eom(); 1678 } 1679 if (reply) { 1680 packet_start(success ? 1681 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1682 packet_put_int(id); 1683 packet_send(); 1684 } 1685 xfree(rtype); 1686 } 1687 static void 1688 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1689 { 1690 char *rtype; 1691 int want_reply; 1692 int success = 0; 1693 1694 rtype = packet_get_string(NULL); 1695 want_reply = packet_get_char(); 1696 debug("client_input_global_request: rtype %s want_reply %d", 1697 rtype, want_reply); 1698 if (want_reply) { 1699 packet_start(success ? 1700 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1701 packet_send(); 1702 packet_write_wait(); 1703 } 1704 xfree(rtype); 1705 } 1706 1707 void 1708 client_session2_setup(int id, int want_tty, int want_subsystem, 1709 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env, 1710 dispatch_fn *subsys_repl) 1711 { 1712 int len; 1713 Channel *c = NULL; 1714 1715 debug2("%s: id %d", __func__, id); 1716 1717 if ((c = channel_lookup(id)) == NULL) 1718 fatal("client_session2_setup: channel %d: unknown channel", id); 1719 1720 if (want_tty) { 1721 struct winsize ws; 1722 struct termios tio; 1723 1724 /* Store window size in the packet. */ 1725 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1726 memset(&ws, 0, sizeof(ws)); 1727 1728 channel_request_start(id, "pty-req", 0); 1729 packet_put_cstring(term != NULL ? term : ""); 1730 packet_put_int(ws.ws_col); 1731 packet_put_int(ws.ws_row); 1732 packet_put_int(ws.ws_xpixel); 1733 packet_put_int(ws.ws_ypixel); 1734 tio = get_saved_tio(); 1735 tty_make_modes(-1, tiop != NULL ? tiop : &tio); 1736 packet_send(); 1737 /* XXX wait for reply */ 1738 c->client_tty = 1; 1739 } 1740 1741 /* Transfer any environment variables from client to server */ 1742 if (options.num_send_env != 0 && env != NULL) { 1743 int i, j, matched; 1744 char *name, *val; 1745 1746 debug("Sending environment."); 1747 for (i = 0; env[i] != NULL; i++) { 1748 /* Split */ 1749 name = xstrdup(env[i]); 1750 if ((val = strchr(name, '=')) == NULL) { 1751 free(name); 1752 continue; 1753 } 1754 *val++ = '\0'; 1755 1756 matched = 0; 1757 for (j = 0; j < options.num_send_env; j++) { 1758 if (match_pattern(name, options.send_env[j])) { 1759 matched = 1; 1760 break; 1761 } 1762 } 1763 if (!matched) { 1764 debug3("Ignored env %s", name); 1765 free(name); 1766 continue; 1767 } 1768 1769 debug("Sending env %s = %s", name, val); 1770 channel_request_start(id, "env", 0); 1771 packet_put_cstring(name); 1772 packet_put_cstring(val); 1773 packet_send(); 1774 free(name); 1775 } 1776 } 1777 1778 len = buffer_len(cmd); 1779 if (len > 0) { 1780 if (len > 900) 1781 len = 900; 1782 if (want_subsystem) { 1783 debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd)); 1784 channel_request_start(id, "subsystem", subsys_repl != NULL); 1785 if (subsys_repl != NULL) { 1786 /* register callback for reply */ 1787 /* XXX we assume that client_loop has already been called */ 1788 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl); 1789 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl); 1790 } 1791 } else { 1792 debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd)); 1793 channel_request_start(id, "exec", 0); 1794 } 1795 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1796 packet_send(); 1797 } else { 1798 channel_request_start(id, "shell", 0); 1799 packet_send(); 1800 } 1801 } 1802 1803 static void 1804 client_init_dispatch_20(void) 1805 { 1806 dispatch_init(&dispatch_protocol_error); 1807 1808 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1809 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1810 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1811 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1812 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1813 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1814 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1815 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1816 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1817 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1818 1819 /* rekeying */ 1820 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1821 1822 /* global request reply messages */ 1823 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 1824 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 1825 } 1826 static void 1827 client_init_dispatch_13(void) 1828 { 1829 dispatch_init(NULL); 1830 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 1831 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 1832 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 1833 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1834 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1835 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 1836 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 1837 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 1838 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 1839 1840 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 1841 &client_input_agent_open : &deny_input_open); 1842 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 1843 &x11_input_open : &deny_input_open); 1844 } 1845 static void 1846 client_init_dispatch_15(void) 1847 { 1848 client_init_dispatch_13(); 1849 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 1850 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 1851 } 1852 static void 1853 client_init_dispatch(void) 1854 { 1855 if (compat20) 1856 client_init_dispatch_20(); 1857 else if (compat13) 1858 client_init_dispatch_13(); 1859 else 1860 client_init_dispatch_15(); 1861 } 1862 1863 /* client specific fatal cleanup */ 1864 void 1865 cleanup_exit(int i) 1866 { 1867 leave_raw_mode(); 1868 leave_non_blocking(); 1869 if (options.control_path != NULL && control_fd != -1) 1870 unlink(options.control_path); 1871 _exit(i); 1872 } 1873