Annotation of src/usr.bin/ssh/clientloop.c, Revision 1.34
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
1.33 deraadt 5: * The main loop for the interactive session (client side).
1.20 markus 6: *
1.33 deraadt 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.
1.20 markus 35: *
36: *
1.33 deraadt 37: * SSH2 support added by Markus Friedl.
38: * Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
1.20 markus 39: *
1.33 deraadt 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"
1.34 ! markus 62: RCSID("$OpenBSD: clientloop.c,v 1.33 2000/09/07 20:27:50 deraadt 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:
1.30 markus 75: #include "buffer.h"
76: #include "bufaux.h"
77:
1.1 deraadt 78: /* Flag indicating that stdin should be redirected from /dev/null. */
79: extern int stdin_null_flag;
80:
1.13 markus 81: /*
82: * Name of the host we are connecting to. This is the name given on the
83: * command line, or the HostName specified for the user-supplied name in a
84: * configuration file.
85: */
1.1 deraadt 86: extern char *host;
87:
1.13 markus 88: /*
89: * Flag to indicate that we have received a window change signal which has
90: * not yet been processed. This will cause a message indicating the new
91: * window size to be sent to the server a little later. This is volatile
92: * because this is updated in a signal handler.
93: */
1.1 deraadt 94: static volatile int received_window_change_signal = 0;
95:
96: /* Terminal modes, as saved by enter_raw_mode. */
97: static struct termios saved_tio;
98:
1.13 markus 99: /*
100: * Flag indicating whether we are in raw mode. This is used by
101: * enter_raw_mode and leave_raw_mode.
102: */
1.1 deraadt 103: static int in_raw_mode = 0;
104:
105: /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
106: static int in_non_blocking_mode = 0;
107:
108: /* Common data for the client loop code. */
1.31 markus 109: static int quit_pending; /* Set to non-zero to quit the client loop. */
110: static int escape_char; /* Escape character. */
1.11 markus 111: static int escape_pending; /* Last character was the escape character */
112: static int last_was_cr; /* Last character was a newline. */
113: static int exit_status; /* Used to store the exit status of the command. */
114: static int stdin_eof; /* EOF has been encountered on standard error. */
115: static Buffer stdin_buffer; /* Buffer for stdin data. */
116: static Buffer stdout_buffer; /* Buffer for stdout data. */
117: static Buffer stderr_buffer; /* Buffer for stderr data. */
1.31 markus 118: static unsigned long stdin_bytes, stdout_bytes, stderr_bytes;
1.11 markus 119: static unsigned int buffer_high;/* Soft max buffer size. */
120: static int max_fd; /* Maximum file descriptor number in select(). */
121: static int connection_in; /* Connection to server (input). */
122: static int connection_out; /* Connection to server (output). */
1.1 deraadt 123:
1.16 markus 124:
125: void client_init_dispatch(void);
126: int session_ident = -1;
127:
1.13 markus 128: /* Returns the user\'s terminal to normal mode if it had been put in raw mode. */
1.1 deraadt 129:
1.20 markus 130: void
1.11 markus 131: leave_raw_mode()
1.1 deraadt 132: {
1.11 markus 133: if (!in_raw_mode)
134: return;
135: in_raw_mode = 0;
136: if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
137: perror("tcsetattr");
1.1 deraadt 138:
1.11 markus 139: fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL);
1.1 deraadt 140: }
141:
142: /* Puts the user\'s terminal in raw mode. */
143:
1.20 markus 144: void
1.11 markus 145: enter_raw_mode()
1.1 deraadt 146: {
1.11 markus 147: struct termios tio;
1.1 deraadt 148:
1.11 markus 149: if (tcgetattr(fileno(stdin), &tio) < 0)
150: perror("tcgetattr");
151: saved_tio = tio;
152: tio.c_iflag |= IGNPAR;
153: tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF);
154: tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL);
1.1 deraadt 155: #ifdef IEXTEN
1.11 markus 156: tio.c_lflag &= ~IEXTEN;
157: #endif /* IEXTEN */
158: tio.c_oflag &= ~OPOST;
159: tio.c_cc[VMIN] = 1;
160: tio.c_cc[VTIME] = 0;
161: if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0)
162: perror("tcsetattr");
163: in_raw_mode = 1;
1.1 deraadt 164:
1.11 markus 165: fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL);
166: }
1.1 deraadt 167:
168: /* Restores stdin to blocking mode. */
169:
1.20 markus 170: void
1.11 markus 171: leave_non_blocking()
1.1 deraadt 172: {
1.11 markus 173: if (in_non_blocking_mode) {
174: (void) fcntl(fileno(stdin), F_SETFL, 0);
175: in_non_blocking_mode = 0;
176: fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL);
177: }
1.1 deraadt 178: }
179:
1.11 markus 180: /* Puts stdin terminal in non-blocking mode. */
181:
1.20 markus 182: void
1.11 markus 183: enter_non_blocking()
1.1 deraadt 184: {
1.11 markus 185: in_non_blocking_mode = 1;
186: (void) fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);
187: fatal_add_cleanup((void (*) (void *)) leave_non_blocking, NULL);
1.1 deraadt 188: }
189:
1.13 markus 190: /*
191: * Signal handler for the window change signal (SIGWINCH). This just sets a
192: * flag indicating that the window has changed.
193: */
1.1 deraadt 194:
1.20 markus 195: void
1.11 markus 196: window_change_handler(int sig)
1.1 deraadt 197: {
1.11 markus 198: received_window_change_signal = 1;
199: signal(SIGWINCH, window_change_handler);
1.1 deraadt 200: }
201:
1.13 markus 202: /*
203: * Signal handler for signals that cause the program to terminate. These
204: * signals must be trapped to restore terminal modes.
205: */
1.1 deraadt 206:
1.20 markus 207: void
1.11 markus 208: signal_handler(int sig)
1.1 deraadt 209: {
1.11 markus 210: if (in_raw_mode)
211: leave_raw_mode();
212: if (in_non_blocking_mode)
213: leave_non_blocking();
214: channel_stop_listening();
215: packet_close();
216: fatal("Killed by signal %d.", sig);
1.1 deraadt 217: }
218:
1.13 markus 219: /*
220: * Returns current time in seconds from Jan 1, 1970 with the maximum
221: * available resolution.
222: */
1.1 deraadt 223:
1.20 markus 224: double
1.11 markus 225: get_current_time()
1.1 deraadt 226: {
1.11 markus 227: struct timeval tv;
228: gettimeofday(&tv, NULL);
229: return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
1.1 deraadt 230: }
231:
1.13 markus 232: /*
233: * This is called when the interactive is entered. This checks if there is
234: * an EOF coming on stdin. We must check this explicitly, as select() does
235: * not appear to wake up when redirecting from /dev/null.
236: */
1.1 deraadt 237:
1.20 markus 238: void
1.11 markus 239: client_check_initial_eof_on_stdin()
1.1 deraadt 240: {
1.11 markus 241: int len;
242: char buf[1];
1.1 deraadt 243:
1.13 markus 244: /*
245: * If standard input is to be "redirected from /dev/null", we simply
246: * mark that we have seen an EOF and send an EOF message to the
247: * server. Otherwise, we try to read a single character; it appears
248: * that for some files, such /dev/null, select() never wakes up for
249: * read for this descriptor, which means that we never get EOF. This
250: * way we will get the EOF if stdin comes from /dev/null or similar.
251: */
1.11 markus 252: if (stdin_null_flag) {
253: /* Fake EOF on stdin. */
254: debug("Sending eof.");
255: stdin_eof = 1;
256: packet_start(SSH_CMSG_EOF);
257: packet_send();
258: } else {
259: enter_non_blocking();
260:
261: /* Check for immediate EOF on stdin. */
262: len = read(fileno(stdin), buf, 1);
263: if (len == 0) {
1.13 markus 264: /* EOF. Record that we have seen it and send EOF to server. */
1.11 markus 265: debug("Sending eof.");
266: stdin_eof = 1;
267: packet_start(SSH_CMSG_EOF);
268: packet_send();
269: } else if (len > 0) {
1.13 markus 270: /*
271: * Got data. We must store the data in the buffer,
272: * and also process it as an escape character if
273: * appropriate.
274: */
1.11 markus 275: if ((unsigned char) buf[0] == escape_char)
276: escape_pending = 1;
277: else {
278: buffer_append(&stdin_buffer, buf, 1);
279: stdin_bytes += 1;
280: }
281: }
282: leave_non_blocking();
283: }
1.1 deraadt 284: }
285:
286:
1.13 markus 287: /*
288: * Make packets from buffered stdin data, and buffer them for sending to the
289: * connection.
290: */
1.1 deraadt 291:
1.20 markus 292: void
1.11 markus 293: client_make_packets_from_stdin_data()
1.1 deraadt 294: {
1.11 markus 295: unsigned int len;
1.1 deraadt 296:
1.11 markus 297: /* Send buffered stdin data to the server. */
298: while (buffer_len(&stdin_buffer) > 0 &&
299: packet_not_very_much_data_to_write()) {
300: len = buffer_len(&stdin_buffer);
301: /* Keep the packets at reasonable size. */
302: if (len > packet_get_maxsize())
303: len = packet_get_maxsize();
304: packet_start(SSH_CMSG_STDIN_DATA);
305: packet_put_string(buffer_ptr(&stdin_buffer), len);
306: packet_send();
307: buffer_consume(&stdin_buffer, len);
308: /* If we have a pending EOF, send it now. */
309: if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
310: packet_start(SSH_CMSG_EOF);
311: packet_send();
312: }
1.1 deraadt 313: }
314: }
315:
1.13 markus 316: /*
317: * Checks if the client window has changed, and sends a packet about it to
318: * the server if so. The actual change is detected elsewhere (by a software
319: * interrupt on Unix); this just checks the flag and sends a message if
320: * appropriate.
321: */
1.1 deraadt 322:
1.20 markus 323: void
1.11 markus 324: client_check_window_change()
1.1 deraadt 325: {
1.16 markus 326: struct winsize ws;
327:
328: if (! received_window_change_signal)
329: return;
330: /** XXX race */
331: received_window_change_signal = 0;
332:
333: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
334: return;
335:
336: debug("client_check_window_change: changed");
337:
338: if (compat20) {
339: channel_request_start(session_ident, "window-change", 0);
340: packet_put_int(ws.ws_col);
341: packet_put_int(ws.ws_row);
342: packet_put_int(ws.ws_xpixel);
343: packet_put_int(ws.ws_ypixel);
344: packet_send();
345: } else {
346: packet_start(SSH_CMSG_WINDOW_SIZE);
347: packet_put_int(ws.ws_row);
348: packet_put_int(ws.ws_col);
349: packet_put_int(ws.ws_xpixel);
350: packet_put_int(ws.ws_ypixel);
351: packet_send();
1.1 deraadt 352: }
353: }
354:
1.13 markus 355: /*
356: * Waits until the client can do something (some data becomes available on
357: * one of the file descriptors).
358: */
1.1 deraadt 359:
1.20 markus 360: void
1.11 markus 361: client_wait_until_can_do_something(fd_set * readset, fd_set * writeset)
362: {
1.16 markus 363: /*debug("client_wait_until_can_do_something"); */
364:
1.11 markus 365: /* Initialize select masks. */
366: FD_ZERO(readset);
1.17 markus 367: FD_ZERO(writeset);
1.11 markus 368:
1.16 markus 369: if (!compat20) {
1.17 markus 370: /* Read from the connection, unless our buffers are full. */
1.16 markus 371: if (buffer_len(&stdout_buffer) < buffer_high &&
372: buffer_len(&stderr_buffer) < buffer_high &&
373: channel_not_very_much_buffered_data())
374: FD_SET(connection_in, readset);
1.17 markus 375: /*
376: * Read from stdin, unless we have seen EOF or have very much
377: * buffered data to send to the server.
378: */
379: if (!stdin_eof && packet_not_very_much_data_to_write())
380: FD_SET(fileno(stdin), readset);
381:
382: /* Select stdout/stderr if have data in buffer. */
383: if (buffer_len(&stdout_buffer) > 0)
384: FD_SET(fileno(stdout), writeset);
385: if (buffer_len(&stderr_buffer) > 0)
386: FD_SET(fileno(stderr), writeset);
1.16 markus 387: } else {
1.11 markus 388: FD_SET(connection_in, readset);
1.16 markus 389: }
1.11 markus 390:
391: /* Add any selections by the channel mechanism. */
392: channel_prepare_select(readset, writeset);
393:
394: /* Select server connection if have data to write to the server. */
395: if (packet_have_data_to_write())
396: FD_SET(connection_out, writeset);
397:
1.16 markus 398: /* move UP XXX */
1.11 markus 399: /* Update maximum file descriptor number, if appropriate. */
400: if (channel_max_fd() > max_fd)
401: max_fd = channel_max_fd();
402:
1.13 markus 403: /*
404: * Wait for something to happen. This will suspend the process until
405: * some selected descriptor can be read, written, or has some other
406: * event pending. Note: if you want to implement SSH_MSG_IGNORE
407: * messages to fool traffic analysis, this might be the place to do
408: * it: just have a random timeout for the select, and send a random
409: * SSH_MSG_IGNORE packet when the timeout expires.
410: */
1.11 markus 411:
412: if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) {
413: char buf[100];
414: /* Some systems fail to clear these automatically. */
415: FD_ZERO(readset);
416: FD_ZERO(writeset);
417: if (errno == EINTR)
418: return;
419: /* Note: we might still have data in the buffers. */
420: snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
421: buffer_append(&stderr_buffer, buf, strlen(buf));
422: stderr_bytes += strlen(buf);
423: quit_pending = 1;
424: }
425: }
426:
1.20 markus 427: void
1.31 markus 428: client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
1.1 deraadt 429: {
1.11 markus 430: struct winsize oldws, newws;
431:
432: /* Flush stdout and stderr buffers. */
1.31 markus 433: if (buffer_len(bout) > 0)
434: atomicio(write, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
435: if (buffer_len(berr) > 0)
436: atomicio(write, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
1.11 markus 437:
438: leave_raw_mode();
439:
1.13 markus 440: /*
441: * Free (and clear) the buffer to reduce the amount of data that gets
442: * written to swap.
443: */
1.31 markus 444: buffer_free(bin);
445: buffer_free(bout);
446: buffer_free(berr);
1.11 markus 447:
448: /* Save old window size. */
449: ioctl(fileno(stdin), TIOCGWINSZ, &oldws);
450:
451: /* Send the suspend signal to the program itself. */
452: kill(getpid(), SIGTSTP);
453:
454: /* Check if the window size has changed. */
455: if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
456: (oldws.ws_row != newws.ws_row ||
457: oldws.ws_col != newws.ws_col ||
458: oldws.ws_xpixel != newws.ws_xpixel ||
459: oldws.ws_ypixel != newws.ws_ypixel))
460: received_window_change_signal = 1;
461:
462: /* OK, we have been continued by the user. Reinitialize buffers. */
1.31 markus 463: buffer_init(bin);
464: buffer_init(bout);
465: buffer_init(berr);
1.11 markus 466:
467: enter_raw_mode();
468: }
469:
1.20 markus 470: void
1.17 markus 471: client_process_net_input(fd_set * readset)
1.11 markus 472: {
1.17 markus 473: int len;
474: char buf[8192];
1.11 markus 475:
1.13 markus 476: /*
477: * Read input from the server, and add any such data to the buffer of
478: * the packet subsystem.
479: */
1.11 markus 480: if (FD_ISSET(connection_in, readset)) {
481: /* Read as much as possible. */
482: len = read(connection_in, buf, sizeof(buf));
1.16 markus 483: /*debug("read connection_in len %d", len); XXX */
1.11 markus 484: if (len == 0) {
485: /* Received EOF. The remote host has closed the connection. */
486: snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
487: host);
1.1 deraadt 488: buffer_append(&stderr_buffer, buf, strlen(buf));
489: stderr_bytes += strlen(buf);
490: quit_pending = 1;
491: return;
1.11 markus 492: }
1.13 markus 493: /*
494: * There is a kernel bug on Solaris that causes select to
495: * sometimes wake up even though there is no data available.
496: */
1.11 markus 497: if (len < 0 && errno == EAGAIN)
498: len = 0;
499:
500: if (len < 0) {
501: /* An error has encountered. Perhaps there is a network problem. */
502: snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
503: host, strerror(errno));
504: buffer_append(&stderr_buffer, buf, strlen(buf));
505: stderr_bytes += strlen(buf);
506: quit_pending = 1;
507: return;
508: }
509: packet_process_incoming(buf, len);
510: }
1.17 markus 511: }
1.16 markus 512:
1.31 markus 513: /* process the characters one by one */
514: int
515: process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
516: {
1.32 markus 517: char string[1024];
1.31 markus 518: pid_t pid;
519: int bytes = 0;
520: unsigned int i;
521: unsigned char ch;
522: char *s;
523:
524: for (i = 0; i < len; i++) {
525: /* Get one character at a time. */
526: ch = buf[i];
527:
528: if (escape_pending) {
529: /* We have previously seen an escape character. */
530: /* Clear the flag now. */
531: escape_pending = 0;
532:
533: /* Process the escaped character. */
534: switch (ch) {
535: case '.':
536: /* Terminate the connection. */
1.32 markus 537: snprintf(string, sizeof string, "%c.\r\n", escape_char);
538: buffer_append(berr, string, strlen(string));
539: /*stderr_bytes += strlen(string); XXX*/
1.31 markus 540:
541: quit_pending = 1;
542: return -1;
543:
544: case 'Z' - 64:
545: /* Suspend the program. */
546: /* Print a message to that effect to the user. */
1.32 markus 547: snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
548: buffer_append(berr, string, strlen(string));
549: /*stderr_bytes += strlen(string); XXX*/
1.31 markus 550:
551: /* Restore terminal modes and suspend. */
552: client_suspend_self(bin, bout, berr);
553:
554: /* We have been continued. */
555: continue;
556:
557: case '&':
558: /* XXX does not work yet with proto 2 */
559: if (compat20)
560: continue;
561: /*
562: * Detach the program (continue to serve connections,
563: * but put in background and no more new connections).
564: */
565: if (!stdin_eof) {
566: /*
567: * Sending SSH_CMSG_EOF alone does not always appear
568: * to be enough. So we try to send an EOF character
569: * first.
570: */
571: packet_start(SSH_CMSG_STDIN_DATA);
572: packet_put_string("\004", 1);
573: packet_send();
574: /* Close stdin. */
575: stdin_eof = 1;
576: if (buffer_len(bin) == 0) {
577: packet_start(SSH_CMSG_EOF);
578: packet_send();
579: }
580: }
581: /* Restore tty modes. */
582: leave_raw_mode();
583:
584: /* Stop listening for new connections. */
585: channel_stop_listening();
586:
587: printf("%c& [backgrounded]\n", escape_char);
588:
589: /* Fork into background. */
590: pid = fork();
591: if (pid < 0) {
592: error("fork: %.100s", strerror(errno));
593: continue;
594: }
595: if (pid != 0) { /* This is the parent. */
596: /* The parent just exits. */
597: exit(0);
598: }
599: /* The child continues serving connections. */
600: continue; /*XXX ? */
601:
602: case '?':
1.32 markus 603: snprintf(string, sizeof string,
1.31 markus 604: "%c?\r\n\
605: Supported escape sequences:\r\n\
606: ~. - terminate connection\r\n\
607: ~^Z - suspend ssh\r\n\
608: ~# - list forwarded connections\r\n\
609: ~& - background ssh (when waiting for connections to terminate)\r\n\
610: ~? - this message\r\n\
611: ~~ - send the escape character by typing it twice\r\n\
612: (Note that escapes are only recognized immediately after newline.)\r\n",
613: escape_char);
1.32 markus 614: buffer_append(berr, string, strlen(string));
1.31 markus 615: continue;
616:
617: case '#':
1.32 markus 618: snprintf(string, sizeof string, "%c#\r\n", escape_char);
619: buffer_append(berr, string, strlen(string));
1.31 markus 620: s = channel_open_message();
621: buffer_append(berr, s, strlen(s));
622: xfree(s);
623: continue;
624:
625: default:
626: if (ch != escape_char) {
627: buffer_put_char(bin, escape_char);
628: bytes++;
629: }
630: /* Escaped characters fall through here */
631: break;
632: }
633: } else {
634: /*
635: * The previous character was not an escape char. Check if this
636: * is an escape.
637: */
638: if (last_was_cr && ch == escape_char) {
639: /* It is. Set the flag and continue to next character. */
640: escape_pending = 1;
641: continue;
642: }
643: }
644:
645: /*
646: * Normal character. Record whether it was a newline,
647: * and append it to the buffer.
648: */
649: last_was_cr = (ch == '\r' || ch == '\n');
650: buffer_put_char(bin, ch);
651: bytes++;
652: }
653: return bytes;
654: }
655:
1.20 markus 656: void
1.17 markus 657: client_process_input(fd_set * readset)
658: {
1.31 markus 659: int ret;
1.21 deraadt 660: int len;
1.31 markus 661: char buf[8192];
1.16 markus 662:
1.11 markus 663: /* Read input from stdin. */
664: if (FD_ISSET(fileno(stdin), readset)) {
665: /* Read as much as possible. */
666: len = read(fileno(stdin), buf, sizeof(buf));
667: if (len <= 0) {
1.13 markus 668: /*
669: * Received EOF or error. They are treated
670: * similarly, except that an error message is printed
671: * if it was an error condition.
672: */
1.11 markus 673: if (len < 0) {
674: snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
675: buffer_append(&stderr_buffer, buf, strlen(buf));
676: stderr_bytes += strlen(buf);
677: }
678: /* Mark that we have seen EOF. */
679: stdin_eof = 1;
1.13 markus 680: /*
681: * Send an EOF message to the server unless there is
682: * data in the buffer. If there is data in the
683: * buffer, no message will be sent now. Code
684: * elsewhere will send the EOF when the buffer
685: * becomes empty if stdin_eof is set.
686: */
1.11 markus 687: if (buffer_len(&stdin_buffer) == 0) {
1.1 deraadt 688: packet_start(SSH_CMSG_EOF);
689: packet_send();
1.11 markus 690: }
691: } else if (escape_char == -1) {
1.13 markus 692: /*
693: * Normal successful read, and no escape character.
694: * Just append the data to buffer.
695: */
1.11 markus 696: buffer_append(&stdin_buffer, buf, len);
697: stdin_bytes += len;
698: } else {
1.13 markus 699: /*
700: * Normal, successful read. But we have an escape character
701: * and have to process the characters one by one.
702: */
1.31 markus 703: ret = process_escapes(&stdin_buffer, &stdout_buffer, &stderr_buffer, buf, len);
704: if (ret == -1)
705: return;
706: stdout_bytes += ret;
1.11 markus 707: }
708: }
709: }
710:
1.20 markus 711: void
1.11 markus 712: client_process_output(fd_set * writeset)
713: {
714: int len;
715: char buf[100];
1.1 deraadt 716:
1.11 markus 717: /* Write buffered output to stdout. */
718: if (FD_ISSET(fileno(stdout), writeset)) {
719: /* Write as much data as possible. */
720: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 721: buffer_len(&stdout_buffer));
1.11 markus 722: if (len <= 0) {
723: if (errno == EAGAIN)
724: len = 0;
725: else {
1.13 markus 726: /*
727: * An error or EOF was encountered. Put an
728: * error message to stderr buffer.
729: */
1.11 markus 730: snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
731: buffer_append(&stderr_buffer, buf, strlen(buf));
732: stderr_bytes += strlen(buf);
733: quit_pending = 1;
734: return;
735: }
736: }
737: /* Consume printed data from the buffer. */
738: buffer_consume(&stdout_buffer, len);
739: }
740: /* Write buffered output to stderr. */
741: if (FD_ISSET(fileno(stderr), writeset)) {
742: /* Write as much data as possible. */
743: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 744: buffer_len(&stderr_buffer));
1.11 markus 745: if (len <= 0) {
746: if (errno == EAGAIN)
747: len = 0;
748: else {
1.13 markus 749: /* EOF or error, but can't even print error message. */
1.11 markus 750: quit_pending = 1;
751: return;
752: }
753: }
754: /* Consume printed characters from the buffer. */
755: buffer_consume(&stderr_buffer, len);
756: }
1.1 deraadt 757: }
758:
1.13 markus 759: /*
1.15 markus 760: * Get packets from the connection input buffer, and process them as long as
761: * there are packets available.
762: *
763: * Any unknown packets received during the actual
764: * session cause the session to terminate. This is
765: * intended to make debugging easier since no
766: * confirmations are sent. Any compatible protocol
767: * extensions must be negotiated during the
768: * preparatory phase.
769: */
770:
1.20 markus 771: void
1.15 markus 772: client_process_buffered_input_packets()
773: {
774: dispatch_run(DISPATCH_NONBLOCK, &quit_pending);
775: }
776:
1.31 markus 777: /* scan buf[] for '~' before sending data to the peer */
1.30 markus 778:
779: int
1.31 markus 780: simple_escape_filter(Channel *c, char *buf, int len)
1.30 markus 781: {
1.31 markus 782: /* XXX we assume c->extended is writeable */
783: return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1.30 markus 784: }
785:
1.15 markus 786: /*
1.13 markus 787: * Implements the interactive session with the server. This is called after
788: * the user has been authenticated, and a command has been started on the
789: * remote host. If escape_char != -1, it is the character used as an escape
790: * character for terminating or suspending the session.
791: */
1.1 deraadt 792:
1.20 markus 793: int
1.30 markus 794: client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1.1 deraadt 795: {
1.11 markus 796: extern Options options;
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:
1.28 provos 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:
1.30 markus 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()) {
855: debug("!channel_still_open.");
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
981: client_input_stdout_data(int type, int plen)
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
992: client_input_stderr_data(int type, int plen)
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
1003: client_input_exit_status(int type, int plen)
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
1021: client_input_channel_open(int type, int plen)
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:
1039: if (strcmp(ctype, "x11") == 0) {
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) {
1.25 markus 1045: debug("buggy server: x11 request w/o originator_port");
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,
1.34 ! markus 1057: sock, sock, -1, CHAN_X11_WINDOW_DEFAULT,
! 1058: CHAN_X11_PACKET_DEFAULT, 0, xstrdup("x11"));
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_AGENT_OPEN, &auth_input_open_request);
1112: dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1113: dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1114: dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1115: dispatch_set(SSH_SMSG_X11_OPEN, &x11_input_open);
1116: }
1.20 markus 1117: void
1.15 markus 1118: client_init_dispatch_15()
1119: {
1120: client_init_dispatch_13();
1121: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1122: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1123: }
1.20 markus 1124: void
1.15 markus 1125: client_init_dispatch()
1126: {
1.16 markus 1127: if (compat20)
1128: client_init_dispatch_20();
1129: else if (compat13)
1.15 markus 1130: client_init_dispatch_13();
1131: else
1132: client_init_dispatch_15();
1.16 markus 1133: }
1134:
1135: void
1136: client_input_channel_req(int id, void *arg)
1137: {
1138: Channel *c = NULL;
1139: unsigned int len;
1140: int success = 0;
1141: int reply;
1142: char *rtype;
1143:
1144: rtype = packet_get_string(&len);
1145: reply = packet_get_char();
1146:
1.23 markus 1147: debug("client_input_channel_req: rtype %s reply %d", rtype, reply);
1.16 markus 1148:
1149: c = channel_lookup(id);
1150: if (c == NULL)
1151: fatal("session_input_channel_req: channel %d: bad channel", id);
1152:
1153: if (session_ident == -1) {
1154: error("client_input_channel_req: no channel %d", id);
1155: } else if (id != session_ident) {
1156: error("client_input_channel_req: bad channel %d != %d",
1157: id, session_ident);
1158: } else if (strcmp(rtype, "exit-status") == 0) {
1159: success = 1;
1160: exit_status = packet_get_int();
1.19 markus 1161: packet_done();
1.16 markus 1162: }
1163: if (reply) {
1164: packet_start(success ?
1165: SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1166: packet_put_int(c->remote_id);
1167: packet_send();
1168: }
1169: xfree(rtype);
1170: }
1171:
1172: void
1173: client_set_session_ident(int id)
1174: {
1175: debug("client_set_session_ident: id %d", id);
1176: session_ident = id;
1177: channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
1178: client_input_channel_req, (void *)0);
1.1 deraadt 1179: }
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