Annotation of src/usr.bin/ssh/clientloop.c, Revision 1.26.2.2
1.1 deraadt 1: /*
1.12 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.26.2.2! jason 5: * The main loop for the interactive session (client side).
1.20 markus 6: *
1.26.2.2! jason 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".
1.20 markus 12: *
13: *
1.26.2.2! jason 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: *
1.20 markus 36: *
1.16 markus 37: * SSH2 support added by Markus Friedl.
1.26.2.2! jason 38: * Copyright (c) 1999,2000 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.
1.12 deraadt 59: */
1.1 deraadt 60:
61: #include "includes.h"
1.26.2.2! jason 62: RCSID("$OpenBSD: clientloop.c,v 1.39 2000/10/27 07:48:22 markus Exp $");
1.1 deraadt 63:
64: #include "xmalloc.h"
65: #include "ssh.h"
66: #include "packet.h"
67: #include "buffer.h"
1.8 markus 68: #include "readconf.h"
1.1 deraadt 69:
1.16 markus 70: #include "ssh2.h"
1.15 markus 71: #include "compat.h"
72: #include "channels.h"
73: #include "dispatch.h"
74:
1.26.2.1 jason 75: #include "buffer.h"
76: #include "bufaux.h"
1.15 markus 77:
1.26.2.2! jason 78:
! 79: /* import options */
! 80: extern Options options;
! 81:
1.1 deraadt 82: /* Flag indicating that stdin should be redirected from /dev/null. */
83: extern int stdin_null_flag;
84:
1.13 markus 85: /*
86: * Name of the host we are connecting to. This is the name given on the
87: * command line, or the HostName specified for the user-supplied name in a
88: * configuration file.
89: */
1.1 deraadt 90: extern char *host;
91:
1.13 markus 92: /*
93: * Flag to indicate that we have received a window change signal which has
94: * not yet been processed. This will cause a message indicating the new
95: * window size to be sent to the server a little later. This is volatile
96: * because this is updated in a signal handler.
97: */
1.1 deraadt 98: static volatile int received_window_change_signal = 0;
99:
100: /* Terminal modes, as saved by enter_raw_mode. */
101: static struct termios saved_tio;
102:
1.13 markus 103: /*
104: * Flag indicating whether we are in raw mode. This is used by
105: * enter_raw_mode and leave_raw_mode.
106: */
1.1 deraadt 107: static int in_raw_mode = 0;
108:
109: /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
110: static int in_non_blocking_mode = 0;
111:
112: /* Common data for the client loop code. */
1.26.2.1 jason 113: static int quit_pending; /* Set to non-zero to quit the client loop. */
114: static int escape_char; /* Escape character. */
1.11 markus 115: static int escape_pending; /* Last character was the escape character */
116: static int last_was_cr; /* Last character was a newline. */
117: static int exit_status; /* Used to store the exit status of the command. */
118: static int stdin_eof; /* EOF has been encountered on standard error. */
119: static Buffer stdin_buffer; /* Buffer for stdin data. */
120: static Buffer stdout_buffer; /* Buffer for stdout data. */
121: static Buffer stderr_buffer; /* Buffer for stderr data. */
1.26.2.1 jason 122: static unsigned long stdin_bytes, stdout_bytes, stderr_bytes;
1.11 markus 123: static unsigned int buffer_high;/* Soft max buffer size. */
124: static int max_fd; /* Maximum file descriptor number in select(). */
125: static int connection_in; /* Connection to server (input). */
126: static int connection_out; /* Connection to server (output). */
1.1 deraadt 127:
1.16 markus 128:
129: void client_init_dispatch(void);
130: int session_ident = -1;
131:
1.13 markus 132: /* Returns the user\'s terminal to normal mode if it had been put in raw mode. */
1.1 deraadt 133:
1.20 markus 134: void
1.11 markus 135: leave_raw_mode()
1.1 deraadt 136: {
1.11 markus 137: if (!in_raw_mode)
138: return;
139: in_raw_mode = 0;
140: if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
141: perror("tcsetattr");
1.1 deraadt 142:
1.11 markus 143: fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL);
1.1 deraadt 144: }
145:
146: /* Puts the user\'s terminal in raw mode. */
147:
1.20 markus 148: void
1.11 markus 149: enter_raw_mode()
1.1 deraadt 150: {
1.11 markus 151: struct termios tio;
1.1 deraadt 152:
1.11 markus 153: if (tcgetattr(fileno(stdin), &tio) < 0)
154: perror("tcgetattr");
155: saved_tio = tio;
156: tio.c_iflag |= IGNPAR;
157: tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF);
158: tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL);
1.1 deraadt 159: #ifdef IEXTEN
1.11 markus 160: tio.c_lflag &= ~IEXTEN;
161: #endif /* IEXTEN */
162: tio.c_oflag &= ~OPOST;
163: tio.c_cc[VMIN] = 1;
164: tio.c_cc[VTIME] = 0;
165: if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0)
166: perror("tcsetattr");
167: in_raw_mode = 1;
1.1 deraadt 168:
1.11 markus 169: fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL);
170: }
1.1 deraadt 171:
172: /* Restores stdin to blocking mode. */
173:
1.20 markus 174: void
1.11 markus 175: leave_non_blocking()
1.1 deraadt 176: {
1.11 markus 177: if (in_non_blocking_mode) {
178: (void) fcntl(fileno(stdin), F_SETFL, 0);
179: in_non_blocking_mode = 0;
180: fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL);
181: }
1.1 deraadt 182: }
183:
1.11 markus 184: /* Puts stdin terminal in non-blocking mode. */
185:
1.20 markus 186: void
1.11 markus 187: enter_non_blocking()
1.1 deraadt 188: {
1.11 markus 189: in_non_blocking_mode = 1;
190: (void) fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);
191: fatal_add_cleanup((void (*) (void *)) leave_non_blocking, NULL);
1.1 deraadt 192: }
193:
1.13 markus 194: /*
195: * Signal handler for the window change signal (SIGWINCH). This just sets a
196: * flag indicating that the window has changed.
197: */
1.1 deraadt 198:
1.20 markus 199: void
1.11 markus 200: window_change_handler(int sig)
1.1 deraadt 201: {
1.11 markus 202: received_window_change_signal = 1;
203: signal(SIGWINCH, window_change_handler);
1.1 deraadt 204: }
205:
1.13 markus 206: /*
207: * Signal handler for signals that cause the program to terminate. These
208: * signals must be trapped to restore terminal modes.
209: */
1.1 deraadt 210:
1.20 markus 211: void
1.11 markus 212: signal_handler(int sig)
1.1 deraadt 213: {
1.11 markus 214: if (in_raw_mode)
215: leave_raw_mode();
216: if (in_non_blocking_mode)
217: leave_non_blocking();
218: channel_stop_listening();
219: packet_close();
220: fatal("Killed by signal %d.", sig);
1.1 deraadt 221: }
222:
1.13 markus 223: /*
224: * Returns current time in seconds from Jan 1, 1970 with the maximum
225: * available resolution.
226: */
1.1 deraadt 227:
1.20 markus 228: double
1.11 markus 229: get_current_time()
1.1 deraadt 230: {
1.11 markus 231: struct timeval tv;
232: gettimeofday(&tv, NULL);
233: return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
1.1 deraadt 234: }
235:
1.13 markus 236: /*
237: * This is called when the interactive is entered. This checks if there is
238: * an EOF coming on stdin. We must check this explicitly, as select() does
239: * not appear to wake up when redirecting from /dev/null.
240: */
1.1 deraadt 241:
1.20 markus 242: void
1.11 markus 243: client_check_initial_eof_on_stdin()
1.1 deraadt 244: {
1.11 markus 245: int len;
246: char buf[1];
1.1 deraadt 247:
1.13 markus 248: /*
249: * If standard input is to be "redirected from /dev/null", we simply
250: * mark that we have seen an EOF and send an EOF message to the
251: * server. Otherwise, we try to read a single character; it appears
252: * that for some files, such /dev/null, select() never wakes up for
253: * read for this descriptor, which means that we never get EOF. This
254: * way we will get the EOF if stdin comes from /dev/null or similar.
255: */
1.11 markus 256: if (stdin_null_flag) {
257: /* Fake EOF on stdin. */
258: debug("Sending eof.");
259: stdin_eof = 1;
260: packet_start(SSH_CMSG_EOF);
261: packet_send();
262: } else {
263: enter_non_blocking();
264:
265: /* Check for immediate EOF on stdin. */
266: len = read(fileno(stdin), buf, 1);
267: if (len == 0) {
1.13 markus 268: /* EOF. Record that we have seen it and send EOF to server. */
1.11 markus 269: debug("Sending eof.");
270: stdin_eof = 1;
271: packet_start(SSH_CMSG_EOF);
272: packet_send();
273: } else if (len > 0) {
1.13 markus 274: /*
275: * Got data. We must store the data in the buffer,
276: * and also process it as an escape character if
277: * appropriate.
278: */
1.11 markus 279: if ((unsigned char) buf[0] == escape_char)
280: escape_pending = 1;
281: else {
282: buffer_append(&stdin_buffer, buf, 1);
283: stdin_bytes += 1;
284: }
285: }
286: leave_non_blocking();
287: }
1.1 deraadt 288: }
289:
290:
1.13 markus 291: /*
292: * Make packets from buffered stdin data, and buffer them for sending to the
293: * connection.
294: */
1.1 deraadt 295:
1.20 markus 296: void
1.11 markus 297: client_make_packets_from_stdin_data()
1.1 deraadt 298: {
1.11 markus 299: unsigned int len;
1.1 deraadt 300:
1.11 markus 301: /* Send buffered stdin data to the server. */
302: while (buffer_len(&stdin_buffer) > 0 &&
303: packet_not_very_much_data_to_write()) {
304: len = buffer_len(&stdin_buffer);
305: /* Keep the packets at reasonable size. */
306: if (len > packet_get_maxsize())
307: len = packet_get_maxsize();
308: packet_start(SSH_CMSG_STDIN_DATA);
309: packet_put_string(buffer_ptr(&stdin_buffer), len);
310: packet_send();
311: buffer_consume(&stdin_buffer, len);
312: /* If we have a pending EOF, send it now. */
313: if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
314: packet_start(SSH_CMSG_EOF);
315: packet_send();
316: }
1.1 deraadt 317: }
318: }
319:
1.13 markus 320: /*
321: * Checks if the client window has changed, and sends a packet about it to
322: * the server if so. The actual change is detected elsewhere (by a software
323: * interrupt on Unix); this just checks the flag and sends a message if
324: * appropriate.
325: */
1.1 deraadt 326:
1.20 markus 327: void
1.11 markus 328: client_check_window_change()
1.1 deraadt 329: {
1.16 markus 330: struct winsize ws;
331:
332: if (! received_window_change_signal)
333: return;
334: /** XXX race */
335: received_window_change_signal = 0;
336:
337: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
338: return;
339:
1.26.2.2! jason 340: debug2("client_check_window_change: changed");
1.16 markus 341:
342: if (compat20) {
343: channel_request_start(session_ident, "window-change", 0);
344: packet_put_int(ws.ws_col);
345: packet_put_int(ws.ws_row);
346: packet_put_int(ws.ws_xpixel);
347: packet_put_int(ws.ws_ypixel);
348: packet_send();
349: } else {
350: packet_start(SSH_CMSG_WINDOW_SIZE);
351: packet_put_int(ws.ws_row);
352: packet_put_int(ws.ws_col);
353: packet_put_int(ws.ws_xpixel);
354: packet_put_int(ws.ws_ypixel);
355: packet_send();
1.1 deraadt 356: }
357: }
358:
1.13 markus 359: /*
360: * Waits until the client can do something (some data becomes available on
361: * one of the file descriptors).
362: */
1.1 deraadt 363:
1.20 markus 364: void
1.11 markus 365: client_wait_until_can_do_something(fd_set * readset, fd_set * writeset)
366: {
367: /* Initialize select masks. */
368: FD_ZERO(readset);
1.17 markus 369: FD_ZERO(writeset);
1.11 markus 370:
1.16 markus 371: if (!compat20) {
1.17 markus 372: /* Read from the connection, unless our buffers are full. */
1.16 markus 373: if (buffer_len(&stdout_buffer) < buffer_high &&
374: buffer_len(&stderr_buffer) < buffer_high &&
375: channel_not_very_much_buffered_data())
376: FD_SET(connection_in, readset);
1.17 markus 377: /*
378: * Read from stdin, unless we have seen EOF or have very much
379: * buffered data to send to the server.
380: */
381: if (!stdin_eof && packet_not_very_much_data_to_write())
382: FD_SET(fileno(stdin), readset);
383:
384: /* Select stdout/stderr if have data in buffer. */
385: if (buffer_len(&stdout_buffer) > 0)
386: FD_SET(fileno(stdout), writeset);
387: if (buffer_len(&stderr_buffer) > 0)
388: FD_SET(fileno(stderr), writeset);
1.16 markus 389: } else {
1.11 markus 390: FD_SET(connection_in, readset);
1.16 markus 391: }
1.11 markus 392:
393: /* Add any selections by the channel mechanism. */
394: channel_prepare_select(readset, writeset);
395:
396: /* Select server connection if have data to write to the server. */
397: if (packet_have_data_to_write())
398: FD_SET(connection_out, writeset);
399:
1.16 markus 400: /* move UP XXX */
1.11 markus 401: /* Update maximum file descriptor number, if appropriate. */
402: if (channel_max_fd() > max_fd)
403: max_fd = channel_max_fd();
404:
1.13 markus 405: /*
406: * Wait for something to happen. This will suspend the process until
407: * some selected descriptor can be read, written, or has some other
408: * event pending. Note: if you want to implement SSH_MSG_IGNORE
409: * messages to fool traffic analysis, this might be the place to do
410: * it: just have a random timeout for the select, and send a random
411: * SSH_MSG_IGNORE packet when the timeout expires.
412: */
1.11 markus 413:
414: if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) {
415: char buf[100];
416: /* Some systems fail to clear these automatically. */
417: FD_ZERO(readset);
418: FD_ZERO(writeset);
419: if (errno == EINTR)
420: return;
421: /* Note: we might still have data in the buffers. */
422: snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
423: buffer_append(&stderr_buffer, buf, strlen(buf));
424: stderr_bytes += strlen(buf);
425: quit_pending = 1;
426: }
427: }
428:
1.20 markus 429: void
1.26.2.1 jason 430: client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
1.1 deraadt 431: {
1.11 markus 432: struct winsize oldws, newws;
433:
434: /* Flush stdout and stderr buffers. */
1.26.2.1 jason 435: if (buffer_len(bout) > 0)
436: atomicio(write, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
437: if (buffer_len(berr) > 0)
438: atomicio(write, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
1.11 markus 439:
440: leave_raw_mode();
441:
1.13 markus 442: /*
443: * Free (and clear) the buffer to reduce the amount of data that gets
444: * written to swap.
445: */
1.26.2.1 jason 446: buffer_free(bin);
447: buffer_free(bout);
448: buffer_free(berr);
1.11 markus 449:
450: /* Save old window size. */
451: ioctl(fileno(stdin), TIOCGWINSZ, &oldws);
452:
453: /* Send the suspend signal to the program itself. */
454: kill(getpid(), SIGTSTP);
455:
456: /* Check if the window size has changed. */
457: if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
458: (oldws.ws_row != newws.ws_row ||
459: oldws.ws_col != newws.ws_col ||
460: oldws.ws_xpixel != newws.ws_xpixel ||
461: oldws.ws_ypixel != newws.ws_ypixel))
462: received_window_change_signal = 1;
463:
464: /* OK, we have been continued by the user. Reinitialize buffers. */
1.26.2.1 jason 465: buffer_init(bin);
466: buffer_init(bout);
467: buffer_init(berr);
1.11 markus 468:
469: enter_raw_mode();
470: }
471:
1.20 markus 472: void
1.17 markus 473: client_process_net_input(fd_set * readset)
1.11 markus 474: {
1.17 markus 475: int len;
476: char buf[8192];
1.11 markus 477:
1.13 markus 478: /*
479: * Read input from the server, and add any such data to the buffer of
480: * the packet subsystem.
481: */
1.11 markus 482: if (FD_ISSET(connection_in, readset)) {
483: /* Read as much as possible. */
484: len = read(connection_in, buf, sizeof(buf));
485: if (len == 0) {
486: /* Received EOF. The remote host has closed the connection. */
487: snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
488: host);
1.1 deraadt 489: buffer_append(&stderr_buffer, buf, strlen(buf));
490: stderr_bytes += strlen(buf);
491: quit_pending = 1;
492: return;
1.11 markus 493: }
1.13 markus 494: /*
495: * There is a kernel bug on Solaris that causes select to
496: * sometimes wake up even though there is no data available.
497: */
1.11 markus 498: if (len < 0 && errno == EAGAIN)
499: len = 0;
500:
501: if (len < 0) {
502: /* An error has encountered. Perhaps there is a network problem. */
503: snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
504: host, strerror(errno));
505: buffer_append(&stderr_buffer, buf, strlen(buf));
506: stderr_bytes += strlen(buf);
507: quit_pending = 1;
508: return;
509: }
510: packet_process_incoming(buf, len);
511: }
1.17 markus 512: }
1.16 markus 513:
1.26.2.1 jason 514: /* process the characters one by one */
515: int
516: process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
517: {
518: char string[1024];
519: pid_t pid;
520: int bytes = 0;
521: unsigned int i;
522: unsigned char ch;
523: char *s;
524:
525: for (i = 0; i < len; i++) {
526: /* Get one character at a time. */
527: ch = buf[i];
528:
529: if (escape_pending) {
530: /* We have previously seen an escape character. */
531: /* Clear the flag now. */
532: escape_pending = 0;
533:
534: /* Process the escaped character. */
535: switch (ch) {
536: case '.':
537: /* Terminate the connection. */
538: snprintf(string, sizeof string, "%c.\r\n", escape_char);
539: buffer_append(berr, string, strlen(string));
540: /*stderr_bytes += strlen(string); XXX*/
541:
542: quit_pending = 1;
543: return -1;
544:
545: case 'Z' - 64:
546: /* Suspend the program. */
547: /* Print a message to that effect to the user. */
548: snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
549: buffer_append(berr, string, strlen(string));
550: /*stderr_bytes += strlen(string); XXX*/
551:
552: /* Restore terminal modes and suspend. */
553: client_suspend_self(bin, bout, berr);
554:
555: /* We have been continued. */
556: continue;
557:
558: case '&':
559: /* XXX does not work yet with proto 2 */
560: if (compat20)
561: continue;
562: /*
563: * Detach the program (continue to serve connections,
564: * but put in background and no more new connections).
565: */
566: if (!stdin_eof) {
567: /*
568: * Sending SSH_CMSG_EOF alone does not always appear
569: * to be enough. So we try to send an EOF character
570: * first.
571: */
572: packet_start(SSH_CMSG_STDIN_DATA);
573: packet_put_string("\004", 1);
574: packet_send();
575: /* Close stdin. */
576: stdin_eof = 1;
577: if (buffer_len(bin) == 0) {
578: packet_start(SSH_CMSG_EOF);
579: packet_send();
580: }
581: }
582: /* Restore tty modes. */
583: leave_raw_mode();
584:
585: /* Stop listening for new connections. */
586: channel_stop_listening();
587:
588: printf("%c& [backgrounded]\n", escape_char);
589:
590: /* Fork into background. */
591: pid = fork();
592: if (pid < 0) {
593: error("fork: %.100s", strerror(errno));
594: continue;
595: }
596: if (pid != 0) { /* This is the parent. */
597: /* The parent just exits. */
598: exit(0);
599: }
600: /* The child continues serving connections. */
601: continue; /*XXX ? */
602:
603: case '?':
604: snprintf(string, sizeof string,
605: "%c?\r\n\
606: Supported escape sequences:\r\n\
607: ~. - terminate connection\r\n\
608: ~^Z - suspend ssh\r\n\
609: ~# - list forwarded connections\r\n\
610: ~& - background ssh (when waiting for connections to terminate)\r\n\
611: ~? - this message\r\n\
612: ~~ - send the escape character by typing it twice\r\n\
613: (Note that escapes are only recognized immediately after newline.)\r\n",
614: escape_char);
615: buffer_append(berr, string, strlen(string));
616: continue;
617:
618: case '#':
619: snprintf(string, sizeof string, "%c#\r\n", escape_char);
620: buffer_append(berr, string, strlen(string));
621: s = channel_open_message();
622: buffer_append(berr, s, strlen(s));
623: xfree(s);
624: continue;
625:
626: default:
627: if (ch != escape_char) {
628: buffer_put_char(bin, escape_char);
629: bytes++;
630: }
631: /* Escaped characters fall through here */
632: break;
633: }
634: } else {
635: /*
636: * The previous character was not an escape char. Check if this
637: * is an escape.
638: */
639: if (last_was_cr && ch == escape_char) {
640: /* It is. Set the flag and continue to next character. */
641: escape_pending = 1;
642: continue;
643: }
644: }
645:
646: /*
647: * Normal character. Record whether it was a newline,
648: * and append it to the buffer.
649: */
650: last_was_cr = (ch == '\r' || ch == '\n');
651: buffer_put_char(bin, ch);
652: bytes++;
653: }
654: return bytes;
655: }
656:
1.20 markus 657: void
1.17 markus 658: client_process_input(fd_set * readset)
659: {
1.26.2.1 jason 660: int ret;
1.21 deraadt 661: int len;
1.26.2.1 jason 662: char buf[8192];
1.16 markus 663:
1.11 markus 664: /* Read input from stdin. */
665: if (FD_ISSET(fileno(stdin), readset)) {
666: /* Read as much as possible. */
667: len = read(fileno(stdin), buf, sizeof(buf));
668: if (len <= 0) {
1.13 markus 669: /*
670: * Received EOF or error. They are treated
671: * similarly, except that an error message is printed
672: * if it was an error condition.
673: */
1.11 markus 674: if (len < 0) {
675: snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
676: buffer_append(&stderr_buffer, buf, strlen(buf));
677: stderr_bytes += strlen(buf);
678: }
679: /* Mark that we have seen EOF. */
680: stdin_eof = 1;
1.13 markus 681: /*
682: * Send an EOF message to the server unless there is
683: * data in the buffer. If there is data in the
684: * buffer, no message will be sent now. Code
685: * elsewhere will send the EOF when the buffer
686: * becomes empty if stdin_eof is set.
687: */
1.11 markus 688: if (buffer_len(&stdin_buffer) == 0) {
1.1 deraadt 689: packet_start(SSH_CMSG_EOF);
690: packet_send();
1.11 markus 691: }
692: } else if (escape_char == -1) {
1.13 markus 693: /*
694: * Normal successful read, and no escape character.
695: * Just append the data to buffer.
696: */
1.11 markus 697: buffer_append(&stdin_buffer, buf, len);
698: stdin_bytes += len;
699: } else {
1.13 markus 700: /*
701: * Normal, successful read. But we have an escape character
702: * and have to process the characters one by one.
703: */
1.26.2.1 jason 704: ret = process_escapes(&stdin_buffer, &stdout_buffer, &stderr_buffer, buf, len);
705: if (ret == -1)
706: return;
707: stdout_bytes += ret;
1.11 markus 708: }
709: }
710: }
711:
1.20 markus 712: void
1.11 markus 713: client_process_output(fd_set * writeset)
714: {
715: int len;
716: char buf[100];
1.1 deraadt 717:
1.11 markus 718: /* Write buffered output to stdout. */
719: if (FD_ISSET(fileno(stdout), writeset)) {
720: /* Write as much data as possible. */
721: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 722: buffer_len(&stdout_buffer));
1.11 markus 723: if (len <= 0) {
724: if (errno == EAGAIN)
725: len = 0;
726: else {
1.13 markus 727: /*
728: * An error or EOF was encountered. Put an
729: * error message to stderr buffer.
730: */
1.11 markus 731: snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
732: buffer_append(&stderr_buffer, buf, strlen(buf));
733: stderr_bytes += strlen(buf);
734: quit_pending = 1;
735: return;
736: }
737: }
738: /* Consume printed data from the buffer. */
739: buffer_consume(&stdout_buffer, len);
740: }
741: /* Write buffered output to stderr. */
742: if (FD_ISSET(fileno(stderr), writeset)) {
743: /* Write as much data as possible. */
744: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 745: buffer_len(&stderr_buffer));
1.11 markus 746: if (len <= 0) {
747: if (errno == EAGAIN)
748: len = 0;
749: else {
1.13 markus 750: /* EOF or error, but can't even print error message. */
1.11 markus 751: quit_pending = 1;
752: return;
753: }
754: }
755: /* Consume printed characters from the buffer. */
756: buffer_consume(&stderr_buffer, len);
757: }
1.1 deraadt 758: }
759:
1.13 markus 760: /*
1.15 markus 761: * Get packets from the connection input buffer, and process them as long as
762: * there are packets available.
763: *
764: * Any unknown packets received during the actual
765: * session cause the session to terminate. This is
766: * intended to make debugging easier since no
767: * confirmations are sent. Any compatible protocol
768: * extensions must be negotiated during the
769: * preparatory phase.
770: */
771:
1.20 markus 772: void
1.15 markus 773: client_process_buffered_input_packets()
774: {
1.26.2.2! jason 775: dispatch_run(DISPATCH_NONBLOCK, &quit_pending, NULL);
1.15 markus 776: }
777:
1.26.2.1 jason 778: /* scan buf[] for '~' before sending data to the peer */
779:
780: int
781: simple_escape_filter(Channel *c, char *buf, int len)
782: {
783: /* XXX we assume c->extended is writeable */
784: return process_escapes(&c->input, &c->output, &c->extended, buf, len);
785: }
786:
1.15 markus 787: /*
1.13 markus 788: * Implements the interactive session with the server. This is called after
789: * the user has been authenticated, and a command has been started on the
790: * remote host. If escape_char != -1, it is the character used as an escape
791: * character for terminating or suspending the session.
792: */
1.1 deraadt 793:
1.20 markus 794: int
1.26.2.1 jason 795: client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1.1 deraadt 796: {
1.11 markus 797: double start_time, total_time;
798: int len;
799: char buf[100];
800:
801: debug("Entering interactive session.");
802:
803: start_time = get_current_time();
804:
805: /* Initialize variables. */
806: escape_pending = 0;
807: last_was_cr = 1;
808: exit_status = -1;
809: stdin_eof = 0;
810: buffer_high = 64 * 1024;
811: connection_in = packet_get_connection_in();
812: connection_out = packet_get_connection_out();
813: max_fd = connection_in;
814: if (connection_out > max_fd)
815: max_fd = connection_out;
816: stdin_bytes = 0;
817: stdout_bytes = 0;
818: stderr_bytes = 0;
819: quit_pending = 0;
820: escape_char = escape_char_arg;
821:
822: /* Initialize buffers. */
823: buffer_init(&stdin_buffer);
824: buffer_init(&stdout_buffer);
825: buffer_init(&stderr_buffer);
826:
1.15 markus 827: client_init_dispatch();
828:
1.11 markus 829: /* Set signal handlers to restore non-blocking mode. */
830: signal(SIGINT, signal_handler);
831: signal(SIGQUIT, signal_handler);
832: signal(SIGTERM, signal_handler);
833: signal(SIGPIPE, SIG_IGN);
834: if (have_pty)
835: signal(SIGWINCH, window_change_handler);
836:
837: if (have_pty)
838: enter_raw_mode();
839:
1.26.2.1 jason 840: /* Check if we should immediately send eof on stdin. */
1.17 markus 841: if (!compat20)
1.16 markus 842: client_check_initial_eof_on_stdin();
1.11 markus 843:
1.26.2.1 jason 844: if (compat20 && escape_char != -1)
845: channel_register_filter(ssh2_chan_id, simple_escape_filter);
846:
1.11 markus 847: /* Main loop of the client for the interactive session mode. */
848: while (!quit_pending) {
849: fd_set readset, writeset;
850:
1.13 markus 851: /* Process buffered packets sent by the server. */
1.11 markus 852: client_process_buffered_input_packets();
853:
1.16 markus 854: if (compat20 && !channel_still_open()) {
1.26.2.2! jason 855: debug2("!channel_still_open.");
1.16 markus 856: break;
857: }
858:
1.13 markus 859: /*
860: * Make packets of buffered stdin data, and buffer them for
861: * sending to the server.
862: */
1.17 markus 863: if (!compat20)
1.16 markus 864: client_make_packets_from_stdin_data();
1.11 markus 865:
1.13 markus 866: /*
867: * Make packets from buffered channel data, and buffer them
868: * for sending to the server.
869: */
1.11 markus 870: if (packet_not_very_much_data_to_write())
871: channel_output_poll();
872:
1.13 markus 873: /*
874: * Check if the window size has changed, and buffer a message
875: * about it to the server if so.
876: */
1.11 markus 877: client_check_window_change();
878:
879: if (quit_pending)
880: break;
881:
1.13 markus 882: /*
883: * Wait until we have something to do (something becomes
884: * available on one of the descriptors).
885: */
1.11 markus 886: client_wait_until_can_do_something(&readset, &writeset);
887:
888: if (quit_pending)
889: break;
890:
891: /* Do channel operations. */
892: channel_after_select(&readset, &writeset);
893:
1.17 markus 894: /* Buffer input from the connection. */
895: client_process_net_input(&readset);
896:
897: if (quit_pending)
898: break;
1.11 markus 899:
1.17 markus 900: if (!compat20) {
901: /* Buffer data from stdin */
902: client_process_input(&readset);
903: /*
904: * Process output to stdout and stderr. Output to
905: * the connection is processed elsewhere (above).
906: */
1.16 markus 907: client_process_output(&writeset);
1.17 markus 908: }
1.11 markus 909:
1.13 markus 910: /* Send as much buffered packet data as possible to the sender. */
1.11 markus 911: if (FD_ISSET(connection_out, &writeset))
912: packet_write_poll();
913: }
914:
915: /* Terminate the session. */
916:
917: /* Stop watching for window change. */
918: if (have_pty)
919: signal(SIGWINCH, SIG_DFL);
920:
921: /* Stop listening for connections. */
922: channel_stop_listening();
923:
1.13 markus 924: /*
925: * In interactive mode (with pseudo tty) display a message indicating
926: * that the connection has been closed.
927: */
1.11 markus 928: if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
929: snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
930: buffer_append(&stderr_buffer, buf, strlen(buf));
931: stderr_bytes += strlen(buf);
932: }
933: /* Output any buffered data for stdout. */
934: while (buffer_len(&stdout_buffer) > 0) {
935: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 936: buffer_len(&stdout_buffer));
1.11 markus 937: if (len <= 0) {
938: error("Write failed flushing stdout buffer.");
939: break;
940: }
941: buffer_consume(&stdout_buffer, len);
942: }
943:
944: /* Output any buffered data for stderr. */
945: while (buffer_len(&stderr_buffer) > 0) {
946: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 947: buffer_len(&stderr_buffer));
1.11 markus 948: if (len <= 0) {
949: error("Write failed flushing stderr buffer.");
950: break;
951: }
952: buffer_consume(&stderr_buffer, len);
953: }
954:
955: if (have_pty)
956: leave_raw_mode();
957:
958: /* Clear and free any buffers. */
959: memset(buf, 0, sizeof(buf));
960: buffer_free(&stdin_buffer);
961: buffer_free(&stdout_buffer);
962: buffer_free(&stderr_buffer);
963:
964: /* Report bytes transferred, and transfer rates. */
965: total_time = get_current_time() - start_time;
966: debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
967: stdin_bytes, stdout_bytes, stderr_bytes, total_time);
968: if (total_time > 0)
969: debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
970: stdin_bytes / total_time, stdout_bytes / total_time,
971: stderr_bytes / total_time);
972:
973: /* Return the exit status of the program. */
974: debug("Exit status %d", exit_status);
975: return exit_status;
1.15 markus 976: }
977:
978: /*********/
979:
980: void
1.26.2.2! jason 981: client_input_stdout_data(int type, int plen, void *ctxt)
1.15 markus 982: {
983: unsigned int data_len;
984: char *data = packet_get_string(&data_len);
985: packet_integrity_check(plen, 4 + data_len, type);
986: buffer_append(&stdout_buffer, data, data_len);
987: stdout_bytes += data_len;
988: memset(data, 0, data_len);
989: xfree(data);
990: }
991: void
1.26.2.2! jason 992: client_input_stderr_data(int type, int plen, void *ctxt)
1.15 markus 993: {
994: unsigned int data_len;
995: char *data = packet_get_string(&data_len);
996: packet_integrity_check(plen, 4 + data_len, type);
997: buffer_append(&stderr_buffer, data, data_len);
998: stdout_bytes += data_len;
999: memset(data, 0, data_len);
1000: xfree(data);
1001: }
1002: void
1.26.2.2! jason 1003: client_input_exit_status(int type, int plen, void *ctxt)
1.15 markus 1004: {
1005: packet_integrity_check(plen, 4, type);
1006: exit_status = packet_get_int();
1007: /* Acknowledge the exit. */
1008: packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1009: packet_send();
1010: /*
1011: * Must wait for packet to be sent since we are
1012: * exiting the loop.
1013: */
1014: packet_write_wait();
1015: /* Flag that we want to exit. */
1016: quit_pending = 1;
1017: }
1018:
1.22 markus 1019: /* XXXX move to generic input handler */
1020: void
1.26.2.2! jason 1021: client_input_channel_open(int type, int plen, void *ctxt)
1.22 markus 1022: {
1023: Channel *c = NULL;
1024: char *ctype;
1025: int id;
1026: unsigned int len;
1027: int rchan;
1028: int rmaxpack;
1029: int rwindow;
1030:
1031: ctype = packet_get_string(&len);
1032: rchan = packet_get_int();
1033: rwindow = packet_get_int();
1034: rmaxpack = packet_get_int();
1035:
1.24 markus 1036: debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1.22 markus 1037: ctype, rchan, rwindow, rmaxpack);
1038:
1.26.2.2! jason 1039: if (strcmp(ctype, "x11") == 0 && options.forward_x11) {
1.22 markus 1040: int sock;
1041: char *originator;
1042: int originator_port;
1043: originator = packet_get_string(NULL);
1.26 markus 1044: if (datafellows & SSH_BUG_X11FWD) {
1.26.2.2! jason 1045: debug2("buggy server: x11 request w/o originator_port");
1.25 markus 1046: originator_port = 0;
1.26 markus 1047: } else {
1048: originator_port = packet_get_int();
1.25 markus 1049: }
1.22 markus 1050: packet_done();
1051: /* XXX check permission */
1052: xfree(originator);
1053: /* XXX move to channels.c */
1054: sock = x11_connect_display();
1055: if (sock >= 0) {
1056: id = channel_new("x11", SSH_CHANNEL_X11_OPEN,
1.26.2.2! jason 1057: sock, sock, -1, CHAN_X11_WINDOW_DEFAULT,
! 1058: CHAN_X11_PACKET_DEFAULT, 0, xstrdup("x11"), 1);
1.22 markus 1059: c = channel_lookup(id);
1060: }
1061: }
1062: /* XXX duplicate : */
1063: if (c != NULL) {
1064: debug("confirm %s", ctype);
1065: c->remote_id = rchan;
1066: c->remote_window = rwindow;
1067: c->remote_maxpacket = rmaxpack;
1068:
1069: packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1070: packet_put_int(c->remote_id);
1071: packet_put_int(c->self);
1072: packet_put_int(c->local_window);
1073: packet_put_int(c->local_maxpacket);
1074: packet_send();
1075: } else {
1076: debug("failure %s", ctype);
1077: packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1078: packet_put_int(rchan);
1079: packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1080: packet_put_cstring("bla bla");
1081: packet_put_cstring("");
1082: packet_send();
1083: }
1084: xfree(ctype);
1085: }
1086:
1.20 markus 1087: void
1.16 markus 1088: client_init_dispatch_20()
1089: {
1090: dispatch_init(&dispatch_protocol_error);
1091: dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1092: dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1093: dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1094: dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1.22 markus 1095: dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1.16 markus 1096: dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1097: dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1098: dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
1099: dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1100: }
1.20 markus 1101: void
1.15 markus 1102: client_init_dispatch_13()
1103: {
1104: dispatch_init(NULL);
1105: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1106: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1107: dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1108: dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1109: dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1110: dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1111: dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1112: dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1113: dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1.26.2.2! jason 1114:
! 1115: dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
! 1116: &auth_input_open_request : &deny_input_open);
! 1117: dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
! 1118: &x11_input_open : &deny_input_open);
1.15 markus 1119: }
1.20 markus 1120: void
1.15 markus 1121: client_init_dispatch_15()
1122: {
1123: client_init_dispatch_13();
1124: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1125: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1126: }
1.20 markus 1127: void
1.15 markus 1128: client_init_dispatch()
1129: {
1.16 markus 1130: if (compat20)
1131: client_init_dispatch_20();
1132: else if (compat13)
1.15 markus 1133: client_init_dispatch_13();
1134: else
1135: client_init_dispatch_15();
1.16 markus 1136: }
1137:
1138: void
1139: client_input_channel_req(int id, void *arg)
1140: {
1141: Channel *c = NULL;
1142: unsigned int len;
1143: int success = 0;
1144: int reply;
1145: char *rtype;
1146:
1147: rtype = packet_get_string(&len);
1148: reply = packet_get_char();
1149:
1.23 markus 1150: debug("client_input_channel_req: rtype %s reply %d", rtype, reply);
1.16 markus 1151:
1152: c = channel_lookup(id);
1153: if (c == NULL)
1.26.2.2! jason 1154: fatal("client_input_channel_req: channel %d: bad channel", id);
1.16 markus 1155:
1156: if (session_ident == -1) {
1157: error("client_input_channel_req: no channel %d", id);
1158: } else if (id != session_ident) {
1159: error("client_input_channel_req: bad channel %d != %d",
1160: id, session_ident);
1161: } else if (strcmp(rtype, "exit-status") == 0) {
1162: success = 1;
1163: exit_status = packet_get_int();
1.19 markus 1164: packet_done();
1.16 markus 1165: }
1166: if (reply) {
1167: packet_start(success ?
1168: SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1169: packet_put_int(c->remote_id);
1170: packet_send();
1171: }
1172: xfree(rtype);
1173: }
1174:
1175: void
1176: client_set_session_ident(int id)
1177: {
1.26.2.2! jason 1178: debug2("client_set_session_ident: id %d", id);
1.16 markus 1179: session_ident = id;
1180: channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
1181: client_input_channel_req, (void *)0);
1.1 deraadt 1182: }
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