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 * Server main loop for handling the interactive session. 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 * SSH2 support by Markus Friedl. 14 * Copyright (c) 2000 Markus Friedl. 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 #include "includes.h" 38 RCSID("$OpenBSD: serverloop.c,v 1.34 2000/10/27 07:32:18 markus Exp $"); 39 40 #include "xmalloc.h" 41 #include "ssh.h" 42 #include "packet.h" 43 #include "buffer.h" 44 #include "servconf.h" 45 #include "pty.h" 46 #include "channels.h" 47 48 #include "compat.h" 49 #include "ssh2.h" 50 #include "session.h" 51 #include "dispatch.h" 52 #include "auth-options.h" 53 54 extern ServerOptions options; 55 56 static Buffer stdin_buffer; /* Buffer for stdin data. */ 57 static Buffer stdout_buffer; /* Buffer for stdout data. */ 58 static Buffer stderr_buffer; /* Buffer for stderr data. */ 59 static int fdin; /* Descriptor for stdin (for writing) */ 60 static int fdout; /* Descriptor for stdout (for reading); 61 May be same number as fdin. */ 62 static int fderr; /* Descriptor for stderr. May be -1. */ 63 static long stdin_bytes = 0; /* Number of bytes written to stdin. */ 64 static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ 65 static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ 66 static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ 67 static int stdin_eof = 0; /* EOF message received from client. */ 68 static int fdout_eof = 0; /* EOF encountered reading from fdout. */ 69 static int fderr_eof = 0; /* EOF encountered readung from fderr. */ 70 static int connection_in; /* Connection to client (input). */ 71 static int connection_out; /* Connection to client (output). */ 72 static unsigned int buffer_high;/* "Soft" max buffer size. */ 73 static int max_fd; /* Max file descriptor number for select(). */ 74 75 /* 76 * This SIGCHLD kludge is used to detect when the child exits. The server 77 * will exit after that, as soon as forwarded connections have terminated. 78 */ 79 80 static pid_t child_pid; /* Pid of the child. */ 81 static volatile int child_terminated; /* The child has terminated. */ 82 static volatile int child_wait_status; /* Status from wait(). */ 83 84 void server_init_dispatch(void); 85 86 void 87 sigchld_handler(int sig) 88 { 89 int save_errno = errno; 90 pid_t wait_pid; 91 92 debug("Received SIGCHLD."); 93 wait_pid = wait((int *) &child_wait_status); 94 if (wait_pid != -1) { 95 if (wait_pid != child_pid) 96 error("Strange, got SIGCHLD and wait returned pid %d but child is %d", 97 wait_pid, child_pid); 98 if (WIFEXITED(child_wait_status) || 99 WIFSIGNALED(child_wait_status)) 100 child_terminated = 1; 101 } 102 signal(SIGCHLD, sigchld_handler); 103 errno = save_errno; 104 } 105 void 106 sigchld_handler2(int sig) 107 { 108 int save_errno = errno; 109 debug("Received SIGCHLD."); 110 child_terminated = 1; 111 signal(SIGCHLD, sigchld_handler2); 112 errno = save_errno; 113 } 114 115 /* 116 * Make packets from buffered stderr data, and buffer it for sending 117 * to the client. 118 */ 119 void 120 make_packets_from_stderr_data() 121 { 122 int len; 123 124 /* Send buffered stderr data to the client. */ 125 while (buffer_len(&stderr_buffer) > 0 && 126 packet_not_very_much_data_to_write()) { 127 len = buffer_len(&stderr_buffer); 128 if (packet_is_interactive()) { 129 if (len > 512) 130 len = 512; 131 } else { 132 /* Keep the packets at reasonable size. */ 133 if (len > packet_get_maxsize()) 134 len = packet_get_maxsize(); 135 } 136 packet_start(SSH_SMSG_STDERR_DATA); 137 packet_put_string(buffer_ptr(&stderr_buffer), len); 138 packet_send(); 139 buffer_consume(&stderr_buffer, len); 140 stderr_bytes += len; 141 } 142 } 143 144 /* 145 * Make packets from buffered stdout data, and buffer it for sending to the 146 * client. 147 */ 148 void 149 make_packets_from_stdout_data() 150 { 151 int len; 152 153 /* Send buffered stdout data to the client. */ 154 while (buffer_len(&stdout_buffer) > 0 && 155 packet_not_very_much_data_to_write()) { 156 len = buffer_len(&stdout_buffer); 157 if (packet_is_interactive()) { 158 if (len > 512) 159 len = 512; 160 } else { 161 /* Keep the packets at reasonable size. */ 162 if (len > packet_get_maxsize()) 163 len = packet_get_maxsize(); 164 } 165 packet_start(SSH_SMSG_STDOUT_DATA); 166 packet_put_string(buffer_ptr(&stdout_buffer), len); 167 packet_send(); 168 buffer_consume(&stdout_buffer, len); 169 stdout_bytes += len; 170 } 171 } 172 173 /* 174 * Sleep in select() until we can do something. This will initialize the 175 * select masks. Upon return, the masks will indicate which descriptors 176 * have data or can accept data. Optionally, a maximum time can be specified 177 * for the duration of the wait (0 = infinite). 178 */ 179 void 180 wait_until_can_do_something(fd_set * readset, fd_set * writeset, 181 unsigned int max_time_milliseconds) 182 { 183 struct timeval tv, *tvp; 184 int ret; 185 186 /* When select fails we restart from here. */ 187 retry_select: 188 189 /* Initialize select() masks. */ 190 FD_ZERO(readset); 191 FD_ZERO(writeset); 192 193 if (compat20) { 194 /* wrong: bad condition XXX */ 195 if (channel_not_very_much_buffered_data()) 196 FD_SET(connection_in, readset); 197 } else { 198 /* 199 * Read packets from the client unless we have too much 200 * buffered stdin or channel data. 201 */ 202 if (buffer_len(&stdin_buffer) < buffer_high && 203 channel_not_very_much_buffered_data()) 204 FD_SET(connection_in, readset); 205 /* 206 * If there is not too much data already buffered going to 207 * the client, try to get some more data from the program. 208 */ 209 if (packet_not_very_much_data_to_write()) { 210 if (!fdout_eof) 211 FD_SET(fdout, readset); 212 if (!fderr_eof) 213 FD_SET(fderr, readset); 214 } 215 /* 216 * If we have buffered data, try to write some of that data 217 * to the program. 218 */ 219 if (fdin != -1 && buffer_len(&stdin_buffer) > 0) 220 FD_SET(fdin, writeset); 221 } 222 /* Set masks for channel descriptors. */ 223 channel_prepare_select(readset, writeset); 224 225 /* 226 * If we have buffered packet data going to the client, mark that 227 * descriptor. 228 */ 229 if (packet_have_data_to_write()) 230 FD_SET(connection_out, writeset); 231 232 /* Update the maximum descriptor number if appropriate. */ 233 if (channel_max_fd() > max_fd) 234 max_fd = channel_max_fd(); 235 236 /* 237 * If child has terminated and there is enough buffer space to read 238 * from it, then read as much as is available and exit. 239 */ 240 if (child_terminated && packet_not_very_much_data_to_write()) 241 if (max_time_milliseconds == 0) 242 max_time_milliseconds = 100; 243 244 if (max_time_milliseconds == 0) 245 tvp = NULL; 246 else { 247 tv.tv_sec = max_time_milliseconds / 1000; 248 tv.tv_usec = 1000 * (max_time_milliseconds % 1000); 249 tvp = &tv; 250 } 251 if (tvp!=NULL) 252 debug("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds); 253 254 /* Wait for something to happen, or the timeout to expire. */ 255 ret = select(max_fd + 1, readset, writeset, NULL, tvp); 256 257 if (ret < 0) { 258 if (errno != EINTR) 259 error("select: %.100s", strerror(errno)); 260 else 261 goto retry_select; 262 } 263 } 264 265 /* 266 * Processes input from the client and the program. Input data is stored 267 * in buffers and processed later. 268 */ 269 void 270 process_input(fd_set * readset) 271 { 272 int len; 273 char buf[16384]; 274 275 /* Read and buffer any input data from the client. */ 276 if (FD_ISSET(connection_in, readset)) { 277 len = read(connection_in, buf, sizeof(buf)); 278 if (len == 0) { 279 verbose("Connection closed by remote host."); 280 fatal_cleanup(); 281 } else if (len < 0) { 282 if (errno != EINTR && errno != EAGAIN) { 283 verbose("Read error from remote host: %.100s", strerror(errno)); 284 fatal_cleanup(); 285 } 286 } else { 287 /* Buffer any received data. */ 288 packet_process_incoming(buf, len); 289 } 290 } 291 if (compat20) 292 return; 293 294 /* Read and buffer any available stdout data from the program. */ 295 if (!fdout_eof && FD_ISSET(fdout, readset)) { 296 len = read(fdout, buf, sizeof(buf)); 297 if (len < 0 && (errno == EINTR || errno == EAGAIN)) { 298 /* do nothing */ 299 } else if (len <= 0) { 300 fdout_eof = 1; 301 } else { 302 buffer_append(&stdout_buffer, buf, len); 303 fdout_bytes += len; 304 } 305 } 306 /* Read and buffer any available stderr data from the program. */ 307 if (!fderr_eof && FD_ISSET(fderr, readset)) { 308 len = read(fderr, buf, sizeof(buf)); 309 if (len < 0 && (errno == EINTR || errno == EAGAIN)) { 310 /* do nothing */ 311 } else if (len <= 0) { 312 fderr_eof = 1; 313 } else { 314 buffer_append(&stderr_buffer, buf, len); 315 } 316 } 317 } 318 319 /* 320 * Sends data from internal buffers to client program stdin. 321 */ 322 void 323 process_output(fd_set * writeset) 324 { 325 int len; 326 327 /* Write buffered data to program stdin. */ 328 if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { 329 len = write(fdin, buffer_ptr(&stdin_buffer), 330 buffer_len(&stdin_buffer)); 331 if (len < 0 && (errno == EINTR || errno == EAGAIN)) { 332 /* do nothing */ 333 } else if (len <= 0) { 334 #ifdef USE_PIPES 335 close(fdin); 336 #else 337 if (fdin != fdout) 338 close(fdin); 339 else 340 shutdown(fdin, SHUT_WR); /* We will no longer send. */ 341 #endif 342 fdin = -1; 343 } else { 344 /* Successful write. Consume the data from the buffer. */ 345 buffer_consume(&stdin_buffer, len); 346 /* Update the count of bytes written to the program. */ 347 stdin_bytes += len; 348 } 349 } 350 /* Send any buffered packet data to the client. */ 351 if (FD_ISSET(connection_out, writeset)) 352 packet_write_poll(); 353 } 354 355 /* 356 * Wait until all buffered output has been sent to the client. 357 * This is used when the program terminates. 358 */ 359 void 360 drain_output() 361 { 362 /* Send any buffered stdout data to the client. */ 363 if (buffer_len(&stdout_buffer) > 0) { 364 packet_start(SSH_SMSG_STDOUT_DATA); 365 packet_put_string(buffer_ptr(&stdout_buffer), 366 buffer_len(&stdout_buffer)); 367 packet_send(); 368 /* Update the count of sent bytes. */ 369 stdout_bytes += buffer_len(&stdout_buffer); 370 } 371 /* Send any buffered stderr data to the client. */ 372 if (buffer_len(&stderr_buffer) > 0) { 373 packet_start(SSH_SMSG_STDERR_DATA); 374 packet_put_string(buffer_ptr(&stderr_buffer), 375 buffer_len(&stderr_buffer)); 376 packet_send(); 377 /* Update the count of sent bytes. */ 378 stderr_bytes += buffer_len(&stderr_buffer); 379 } 380 /* Wait until all buffered data has been written to the client. */ 381 packet_write_wait(); 382 } 383 384 void 385 process_buffered_input_packets() 386 { 387 dispatch_run(DISPATCH_NONBLOCK, NULL, NULL); 388 } 389 390 /* 391 * Performs the interactive session. This handles data transmission between 392 * the client and the program. Note that the notion of stdin, stdout, and 393 * stderr in this function is sort of reversed: this function writes to 394 * stdin (of the child program), and reads from stdout and stderr (of the 395 * child program). 396 */ 397 void 398 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) 399 { 400 fd_set readset, writeset; 401 int wait_status; /* Status returned by wait(). */ 402 pid_t wait_pid; /* pid returned by wait(). */ 403 int waiting_termination = 0; /* Have displayed waiting close message. */ 404 unsigned int max_time_milliseconds; 405 unsigned int previous_stdout_buffer_bytes; 406 unsigned int stdout_buffer_bytes; 407 int type; 408 409 debug("Entering interactive session."); 410 411 /* Initialize the SIGCHLD kludge. */ 412 child_pid = pid; 413 child_terminated = 0; 414 signal(SIGCHLD, sigchld_handler); 415 416 /* Initialize our global variables. */ 417 fdin = fdin_arg; 418 fdout = fdout_arg; 419 fderr = fderr_arg; 420 421 /* nonblocking IO */ 422 set_nonblock(fdin); 423 set_nonblock(fdout); 424 /* we don't have stderr for interactive terminal sessions, see below */ 425 if (fderr != -1) 426 set_nonblock(fderr); 427 428 connection_in = packet_get_connection_in(); 429 connection_out = packet_get_connection_out(); 430 431 previous_stdout_buffer_bytes = 0; 432 433 /* Set approximate I/O buffer size. */ 434 if (packet_is_interactive()) 435 buffer_high = 4096; 436 else 437 buffer_high = 64 * 1024; 438 439 /* Initialize max_fd to the maximum of the known file descriptors. */ 440 max_fd = fdin; 441 if (fdout > max_fd) 442 max_fd = fdout; 443 if (fderr != -1 && fderr > max_fd) 444 max_fd = fderr; 445 if (connection_in > max_fd) 446 max_fd = connection_in; 447 if (connection_out > max_fd) 448 max_fd = connection_out; 449 450 /* Initialize Initialize buffers. */ 451 buffer_init(&stdin_buffer); 452 buffer_init(&stdout_buffer); 453 buffer_init(&stderr_buffer); 454 455 /* 456 * If we have no separate fderr (which is the case when we have a pty 457 * - there we cannot make difference between data sent to stdout and 458 * stderr), indicate that we have seen an EOF from stderr. This way 459 * we don\'t need to check the descriptor everywhere. 460 */ 461 if (fderr == -1) 462 fderr_eof = 1; 463 464 server_init_dispatch(); 465 466 /* Main loop of the server for the interactive session mode. */ 467 for (;;) { 468 469 /* Process buffered packets from the client. */ 470 process_buffered_input_packets(); 471 472 /* 473 * If we have received eof, and there is no more pending 474 * input data, cause a real eof by closing fdin. 475 */ 476 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { 477 #ifdef USE_PIPES 478 close(fdin); 479 #else 480 if (fdin != fdout) 481 close(fdin); 482 else 483 shutdown(fdin, SHUT_WR); /* We will no longer send. */ 484 #endif 485 fdin = -1; 486 } 487 /* Make packets from buffered stderr data to send to the client. */ 488 make_packets_from_stderr_data(); 489 490 /* 491 * Make packets from buffered stdout data to send to the 492 * client. If there is very little to send, this arranges to 493 * not send them now, but to wait a short while to see if we 494 * are getting more data. This is necessary, as some systems 495 * wake up readers from a pty after each separate character. 496 */ 497 max_time_milliseconds = 0; 498 stdout_buffer_bytes = buffer_len(&stdout_buffer); 499 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && 500 stdout_buffer_bytes != previous_stdout_buffer_bytes) { 501 /* try again after a while */ 502 max_time_milliseconds = 10; 503 } else { 504 /* Send it now. */ 505 make_packets_from_stdout_data(); 506 } 507 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); 508 509 /* Send channel data to the client. */ 510 if (packet_not_very_much_data_to_write()) 511 channel_output_poll(); 512 513 /* 514 * Bail out of the loop if the program has closed its output 515 * descriptors, and we have no more data to send to the 516 * client, and there is no pending buffered data. 517 */ 518 if (fdout_eof && fderr_eof && !packet_have_data_to_write() && 519 buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) { 520 if (!channel_still_open()) 521 break; 522 if (!waiting_termination) { 523 const char *s = "Waiting for forwarded connections to terminate...\r\n"; 524 char *cp; 525 waiting_termination = 1; 526 buffer_append(&stderr_buffer, s, strlen(s)); 527 528 /* Display list of open channels. */ 529 cp = channel_open_message(); 530 buffer_append(&stderr_buffer, cp, strlen(cp)); 531 xfree(cp); 532 } 533 } 534 /* Sleep in select() until we can do something. */ 535 wait_until_can_do_something(&readset, &writeset, 536 max_time_milliseconds); 537 538 /* Process any channel events. */ 539 channel_after_select(&readset, &writeset); 540 541 /* Process input from the client and from program stdout/stderr. */ 542 process_input(&readset); 543 544 /* Process output to the client and to program stdin. */ 545 process_output(&writeset); 546 } 547 548 /* Cleanup and termination code. */ 549 550 /* Wait until all output has been sent to the client. */ 551 drain_output(); 552 553 debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", 554 stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); 555 556 /* Free and clear the buffers. */ 557 buffer_free(&stdin_buffer); 558 buffer_free(&stdout_buffer); 559 buffer_free(&stderr_buffer); 560 561 /* Close the file descriptors. */ 562 if (fdout != -1) 563 close(fdout); 564 fdout = -1; 565 fdout_eof = 1; 566 if (fderr != -1) 567 close(fderr); 568 fderr = -1; 569 fderr_eof = 1; 570 if (fdin != -1) 571 close(fdin); 572 fdin = -1; 573 574 /* Stop listening for channels; this removes unix domain sockets. */ 575 channel_stop_listening(); 576 577 /* Wait for the child to exit. Get its exit status. */ 578 wait_pid = wait(&wait_status); 579 if (wait_pid < 0) { 580 /* 581 * It is possible that the wait was handled by SIGCHLD 582 * handler. This may result in either: this call 583 * returning with EINTR, or: this call returning ECHILD. 584 */ 585 if (child_terminated) 586 wait_status = child_wait_status; 587 else 588 packet_disconnect("wait: %.100s", strerror(errno)); 589 } else { 590 /* Check if it matches the process we forked. */ 591 if (wait_pid != pid) 592 error("Strange, wait returned pid %d, expected %d", 593 wait_pid, pid); 594 } 595 596 /* We no longer want our SIGCHLD handler to be called. */ 597 signal(SIGCHLD, SIG_DFL); 598 599 /* Check if it exited normally. */ 600 if (WIFEXITED(wait_status)) { 601 /* Yes, normal exit. Get exit status and send it to the client. */ 602 debug("Command exited with status %d.", WEXITSTATUS(wait_status)); 603 packet_start(SSH_SMSG_EXITSTATUS); 604 packet_put_int(WEXITSTATUS(wait_status)); 605 packet_send(); 606 packet_write_wait(); 607 608 /* 609 * Wait for exit confirmation. Note that there might be 610 * other packets coming before it; however, the program has 611 * already died so we just ignore them. The client is 612 * supposed to respond with the confirmation when it receives 613 * the exit status. 614 */ 615 do { 616 int plen; 617 type = packet_read(&plen); 618 } 619 while (type != SSH_CMSG_EXIT_CONFIRMATION); 620 621 debug("Received exit confirmation."); 622 return; 623 } 624 /* Check if the program terminated due to a signal. */ 625 if (WIFSIGNALED(wait_status)) 626 packet_disconnect("Command terminated on signal %d.", 627 WTERMSIG(wait_status)); 628 629 /* Some weird exit cause. Just exit. */ 630 packet_disconnect("wait returned status %04x.", wait_status); 631 /* NOTREACHED */ 632 } 633 634 void 635 server_loop2(void) 636 { 637 fd_set readset, writeset; 638 int had_channel = 0; 639 int status; 640 pid_t pid; 641 642 debug("Entering interactive session for SSH2."); 643 644 signal(SIGCHLD, sigchld_handler2); 645 child_terminated = 0; 646 connection_in = packet_get_connection_in(); 647 connection_out = packet_get_connection_out(); 648 max_fd = connection_in; 649 if (connection_out > max_fd) 650 max_fd = connection_out; 651 server_init_dispatch(); 652 653 for (;;) { 654 process_buffered_input_packets(); 655 if (!had_channel && channel_still_open()) 656 had_channel = 1; 657 if (had_channel && !channel_still_open()) { 658 debug("!channel_still_open."); 659 break; 660 } 661 if (packet_not_very_much_data_to_write()) 662 channel_output_poll(); 663 wait_until_can_do_something(&readset, &writeset, 0); 664 if (child_terminated) { 665 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) 666 session_close_by_pid(pid, status); 667 child_terminated = 0; 668 } 669 channel_after_select(&readset, &writeset); 670 process_input(&readset); 671 process_output(&writeset); 672 } 673 signal(SIGCHLD, SIG_DFL); 674 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) 675 session_close_by_pid(pid, status); 676 channel_stop_listening(); 677 } 678 679 void 680 server_input_stdin_data(int type, int plen, void *ctxt) 681 { 682 char *data; 683 unsigned int data_len; 684 685 /* Stdin data from the client. Append it to the buffer. */ 686 /* Ignore any data if the client has closed stdin. */ 687 if (fdin == -1) 688 return; 689 data = packet_get_string(&data_len); 690 packet_integrity_check(plen, (4 + data_len), type); 691 buffer_append(&stdin_buffer, data, data_len); 692 memset(data, 0, data_len); 693 xfree(data); 694 } 695 696 void 697 server_input_eof(int type, int plen, void *ctxt) 698 { 699 /* 700 * Eof from the client. The stdin descriptor to the 701 * program will be closed when all buffered data has 702 * drained. 703 */ 704 debug("EOF received for stdin."); 705 packet_integrity_check(plen, 0, type); 706 stdin_eof = 1; 707 } 708 709 void 710 server_input_window_size(int type, int plen, void *ctxt) 711 { 712 int row = packet_get_int(); 713 int col = packet_get_int(); 714 int xpixel = packet_get_int(); 715 int ypixel = packet_get_int(); 716 717 debug("Window change received."); 718 packet_integrity_check(plen, 4 * 4, type); 719 if (fdin != -1) 720 pty_change_window_size(fdin, row, col, xpixel, ypixel); 721 } 722 723 int 724 input_direct_tcpip(void) 725 { 726 int sock; 727 char *target, *originator; 728 int target_port, originator_port; 729 730 target = packet_get_string(NULL); 731 target_port = packet_get_int(); 732 originator = packet_get_string(NULL); 733 originator_port = packet_get_int(); 734 packet_done(); 735 736 debug("open direct-tcpip: from %s port %d to %s port %d", 737 originator, originator_port, target, target_port); 738 739 /* XXX check permission */ 740 if (no_port_forwarding_flag || !options.allow_tcp_forwarding) { 741 xfree(target); 742 xfree(originator); 743 return -1; 744 } 745 sock = channel_connect_to(target, target_port); 746 xfree(target); 747 xfree(originator); 748 if (sock < 0) 749 return -1; 750 return channel_new("direct-tcpip", SSH_CHANNEL_OPEN, 751 sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, 752 CHAN_TCP_PACKET_DEFAULT, 0, xstrdup("direct-tcpip"), 1); 753 } 754 755 void 756 server_input_channel_open(int type, int plen, void *ctxt) 757 { 758 Channel *c = NULL; 759 char *ctype; 760 int id; 761 unsigned int len; 762 int rchan; 763 int rmaxpack; 764 int rwindow; 765 766 ctype = packet_get_string(&len); 767 rchan = packet_get_int(); 768 rwindow = packet_get_int(); 769 rmaxpack = packet_get_int(); 770 771 debug("server_input_channel_open: ctype %s rchan %d win %d max %d", 772 ctype, rchan, rwindow, rmaxpack); 773 774 if (strcmp(ctype, "session") == 0) { 775 debug("open session"); 776 packet_done(); 777 /* 778 * A server session has no fd to read or write 779 * until a CHANNEL_REQUEST for a shell is made, 780 * so we set the type to SSH_CHANNEL_LARVAL. 781 * Additionally, a callback for handling all 782 * CHANNEL_REQUEST messages is registered. 783 */ 784 id = channel_new(ctype, SSH_CHANNEL_LARVAL, 785 -1, -1, -1, 0, CHAN_SES_PACKET_DEFAULT, 786 0, xstrdup("server-session"), 1); 787 if (session_open(id) == 1) { 788 channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST, 789 session_input_channel_req, (void *)0); 790 channel_register_cleanup(id, session_close_by_channel); 791 c = channel_lookup(id); 792 } else { 793 debug("session open failed, free channel %d", id); 794 channel_free(id); 795 } 796 } else if (strcmp(ctype, "direct-tcpip") == 0) { 797 id = input_direct_tcpip(); 798 if (id >= 0) 799 c = channel_lookup(id); 800 } 801 if (c != NULL) { 802 debug("confirm %s", ctype); 803 c->remote_id = rchan; 804 c->remote_window = rwindow; 805 c->remote_maxpacket = rmaxpack; 806 807 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 808 packet_put_int(c->remote_id); 809 packet_put_int(c->self); 810 packet_put_int(c->local_window); 811 packet_put_int(c->local_maxpacket); 812 packet_send(); 813 } else { 814 debug("failure %s", ctype); 815 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 816 packet_put_int(rchan); 817 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 818 packet_put_cstring("bla bla"); 819 packet_put_cstring(""); 820 packet_send(); 821 } 822 xfree(ctype); 823 } 824 825 void 826 server_init_dispatch_20() 827 { 828 debug("server_init_dispatch_20"); 829 dispatch_init(&dispatch_protocol_error); 830 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 831 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 832 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 833 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 834 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); 835 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 836 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 837 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); 838 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 839 } 840 void 841 server_init_dispatch_13() 842 { 843 debug("server_init_dispatch_13"); 844 dispatch_init(NULL); 845 dispatch_set(SSH_CMSG_EOF, &server_input_eof); 846 dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); 847 dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); 848 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 849 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 850 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 851 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 852 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 853 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 854 } 855 void 856 server_init_dispatch_15() 857 { 858 server_init_dispatch_13(); 859 debug("server_init_dispatch_15"); 860 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 861 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); 862 } 863 void 864 server_init_dispatch() 865 { 866 if (compat20) 867 server_init_dispatch_20(); 868 else if (compat13) 869 server_init_dispatch_13(); 870 else 871 server_init_dispatch_15(); 872 } 873