Annotation of src/usr.bin/ssh/clientloop.c, Revision 1.38
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"
1.38 ! markus 62: RCSID("$OpenBSD: clientloop.c,v 1.37 2000/09/26 19:59:58 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:
1.30 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:
1.37 markus 336: debug2("client_check_window_change: changed");
1.16 markus 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: {
363: /* Initialize select masks. */
364: FD_ZERO(readset);
1.17 markus 365: FD_ZERO(writeset);
1.11 markus 366:
1.16 markus 367: if (!compat20) {
1.17 markus 368: /* Read from the connection, unless our buffers are full. */
1.16 markus 369: if (buffer_len(&stdout_buffer) < buffer_high &&
370: buffer_len(&stderr_buffer) < buffer_high &&
371: channel_not_very_much_buffered_data())
372: FD_SET(connection_in, readset);
1.17 markus 373: /*
374: * Read from stdin, unless we have seen EOF or have very much
375: * buffered data to send to the server.
376: */
377: if (!stdin_eof && packet_not_very_much_data_to_write())
378: FD_SET(fileno(stdin), readset);
379:
380: /* Select stdout/stderr if have data in buffer. */
381: if (buffer_len(&stdout_buffer) > 0)
382: FD_SET(fileno(stdout), writeset);
383: if (buffer_len(&stderr_buffer) > 0)
384: FD_SET(fileno(stderr), writeset);
1.16 markus 385: } else {
1.11 markus 386: FD_SET(connection_in, readset);
1.16 markus 387: }
1.11 markus 388:
389: /* Add any selections by the channel mechanism. */
390: channel_prepare_select(readset, writeset);
391:
392: /* Select server connection if have data to write to the server. */
393: if (packet_have_data_to_write())
394: FD_SET(connection_out, writeset);
395:
1.16 markus 396: /* move UP XXX */
1.11 markus 397: /* Update maximum file descriptor number, if appropriate. */
398: if (channel_max_fd() > max_fd)
399: max_fd = channel_max_fd();
400:
1.13 markus 401: /*
402: * Wait for something to happen. This will suspend the process until
403: * some selected descriptor can be read, written, or has some other
404: * event pending. Note: if you want to implement SSH_MSG_IGNORE
405: * messages to fool traffic analysis, this might be the place to do
406: * it: just have a random timeout for the select, and send a random
407: * SSH_MSG_IGNORE packet when the timeout expires.
408: */
1.11 markus 409:
410: if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) {
411: char buf[100];
412: /* Some systems fail to clear these automatically. */
413: FD_ZERO(readset);
414: FD_ZERO(writeset);
415: if (errno == EINTR)
416: return;
417: /* Note: we might still have data in the buffers. */
418: snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
419: buffer_append(&stderr_buffer, buf, strlen(buf));
420: stderr_bytes += strlen(buf);
421: quit_pending = 1;
422: }
423: }
424:
1.20 markus 425: void
1.31 markus 426: client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
1.1 deraadt 427: {
1.11 markus 428: struct winsize oldws, newws;
429:
430: /* Flush stdout and stderr buffers. */
1.31 markus 431: if (buffer_len(bout) > 0)
432: atomicio(write, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
433: if (buffer_len(berr) > 0)
434: atomicio(write, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
1.11 markus 435:
436: leave_raw_mode();
437:
1.13 markus 438: /*
439: * Free (and clear) the buffer to reduce the amount of data that gets
440: * written to swap.
441: */
1.31 markus 442: buffer_free(bin);
443: buffer_free(bout);
444: buffer_free(berr);
1.11 markus 445:
446: /* Save old window size. */
447: ioctl(fileno(stdin), TIOCGWINSZ, &oldws);
448:
449: /* Send the suspend signal to the program itself. */
450: kill(getpid(), SIGTSTP);
451:
452: /* Check if the window size has changed. */
453: if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
454: (oldws.ws_row != newws.ws_row ||
455: oldws.ws_col != newws.ws_col ||
456: oldws.ws_xpixel != newws.ws_xpixel ||
457: oldws.ws_ypixel != newws.ws_ypixel))
458: received_window_change_signal = 1;
459:
460: /* OK, we have been continued by the user. Reinitialize buffers. */
1.31 markus 461: buffer_init(bin);
462: buffer_init(bout);
463: buffer_init(berr);
1.11 markus 464:
465: enter_raw_mode();
466: }
467:
1.20 markus 468: void
1.17 markus 469: client_process_net_input(fd_set * readset)
1.11 markus 470: {
1.17 markus 471: int len;
472: char buf[8192];
1.11 markus 473:
1.13 markus 474: /*
475: * Read input from the server, and add any such data to the buffer of
476: * the packet subsystem.
477: */
1.11 markus 478: if (FD_ISSET(connection_in, readset)) {
479: /* Read as much as possible. */
480: len = read(connection_in, buf, sizeof(buf));
481: if (len == 0) {
482: /* Received EOF. The remote host has closed the connection. */
483: snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
484: host);
1.1 deraadt 485: buffer_append(&stderr_buffer, buf, strlen(buf));
486: stderr_bytes += strlen(buf);
487: quit_pending = 1;
488: return;
1.11 markus 489: }
1.13 markus 490: /*
491: * There is a kernel bug on Solaris that causes select to
492: * sometimes wake up even though there is no data available.
493: */
1.11 markus 494: if (len < 0 && errno == EAGAIN)
495: len = 0;
496:
497: if (len < 0) {
498: /* An error has encountered. Perhaps there is a network problem. */
499: snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
500: host, strerror(errno));
501: buffer_append(&stderr_buffer, buf, strlen(buf));
502: stderr_bytes += strlen(buf);
503: quit_pending = 1;
504: return;
505: }
506: packet_process_incoming(buf, len);
507: }
1.17 markus 508: }
1.16 markus 509:
1.31 markus 510: /* process the characters one by one */
511: int
512: process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
513: {
1.32 markus 514: char string[1024];
1.31 markus 515: pid_t pid;
516: int bytes = 0;
517: unsigned int i;
518: unsigned char ch;
519: char *s;
520:
521: for (i = 0; i < len; i++) {
522: /* Get one character at a time. */
523: ch = buf[i];
524:
525: if (escape_pending) {
526: /* We have previously seen an escape character. */
527: /* Clear the flag now. */
528: escape_pending = 0;
529:
530: /* Process the escaped character. */
531: switch (ch) {
532: case '.':
533: /* Terminate the connection. */
1.32 markus 534: snprintf(string, sizeof string, "%c.\r\n", escape_char);
535: buffer_append(berr, string, strlen(string));
536: /*stderr_bytes += strlen(string); XXX*/
1.31 markus 537:
538: quit_pending = 1;
539: return -1;
540:
541: case 'Z' - 64:
542: /* Suspend the program. */
543: /* Print a message to that effect to the user. */
1.32 markus 544: snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
545: buffer_append(berr, string, strlen(string));
546: /*stderr_bytes += strlen(string); XXX*/
1.31 markus 547:
548: /* Restore terminal modes and suspend. */
549: client_suspend_self(bin, bout, berr);
550:
551: /* We have been continued. */
552: continue;
553:
554: case '&':
555: /* XXX does not work yet with proto 2 */
556: if (compat20)
557: continue;
558: /*
559: * Detach the program (continue to serve connections,
560: * but put in background and no more new connections).
561: */
562: if (!stdin_eof) {
563: /*
564: * Sending SSH_CMSG_EOF alone does not always appear
565: * to be enough. So we try to send an EOF character
566: * first.
567: */
568: packet_start(SSH_CMSG_STDIN_DATA);
569: packet_put_string("\004", 1);
570: packet_send();
571: /* Close stdin. */
572: stdin_eof = 1;
573: if (buffer_len(bin) == 0) {
574: packet_start(SSH_CMSG_EOF);
575: packet_send();
576: }
577: }
578: /* Restore tty modes. */
579: leave_raw_mode();
580:
581: /* Stop listening for new connections. */
582: channel_stop_listening();
583:
584: printf("%c& [backgrounded]\n", escape_char);
585:
586: /* Fork into background. */
587: pid = fork();
588: if (pid < 0) {
589: error("fork: %.100s", strerror(errno));
590: continue;
591: }
592: if (pid != 0) { /* This is the parent. */
593: /* The parent just exits. */
594: exit(0);
595: }
596: /* The child continues serving connections. */
597: continue; /*XXX ? */
598:
599: case '?':
1.32 markus 600: snprintf(string, sizeof string,
1.31 markus 601: "%c?\r\n\
602: Supported escape sequences:\r\n\
603: ~. - terminate connection\r\n\
604: ~^Z - suspend ssh\r\n\
605: ~# - list forwarded connections\r\n\
606: ~& - background ssh (when waiting for connections to terminate)\r\n\
607: ~? - this message\r\n\
608: ~~ - send the escape character by typing it twice\r\n\
609: (Note that escapes are only recognized immediately after newline.)\r\n",
610: escape_char);
1.32 markus 611: buffer_append(berr, string, strlen(string));
1.31 markus 612: continue;
613:
614: case '#':
1.32 markus 615: snprintf(string, sizeof string, "%c#\r\n", escape_char);
616: buffer_append(berr, string, strlen(string));
1.31 markus 617: s = channel_open_message();
618: buffer_append(berr, s, strlen(s));
619: xfree(s);
620: continue;
621:
622: default:
623: if (ch != escape_char) {
624: buffer_put_char(bin, escape_char);
625: bytes++;
626: }
627: /* Escaped characters fall through here */
628: break;
629: }
630: } else {
631: /*
632: * The previous character was not an escape char. Check if this
633: * is an escape.
634: */
635: if (last_was_cr && ch == escape_char) {
636: /* It is. Set the flag and continue to next character. */
637: escape_pending = 1;
638: continue;
639: }
640: }
641:
642: /*
643: * Normal character. Record whether it was a newline,
644: * and append it to the buffer.
645: */
646: last_was_cr = (ch == '\r' || ch == '\n');
647: buffer_put_char(bin, ch);
648: bytes++;
649: }
650: return bytes;
651: }
652:
1.20 markus 653: void
1.17 markus 654: client_process_input(fd_set * readset)
655: {
1.31 markus 656: int ret;
1.21 deraadt 657: int len;
1.31 markus 658: char buf[8192];
1.16 markus 659:
1.11 markus 660: /* Read input from stdin. */
661: if (FD_ISSET(fileno(stdin), readset)) {
662: /* Read as much as possible. */
663: len = read(fileno(stdin), buf, sizeof(buf));
664: if (len <= 0) {
1.13 markus 665: /*
666: * Received EOF or error. They are treated
667: * similarly, except that an error message is printed
668: * if it was an error condition.
669: */
1.11 markus 670: if (len < 0) {
671: snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
672: buffer_append(&stderr_buffer, buf, strlen(buf));
673: stderr_bytes += strlen(buf);
674: }
675: /* Mark that we have seen EOF. */
676: stdin_eof = 1;
1.13 markus 677: /*
678: * Send an EOF message to the server unless there is
679: * data in the buffer. If there is data in the
680: * buffer, no message will be sent now. Code
681: * elsewhere will send the EOF when the buffer
682: * becomes empty if stdin_eof is set.
683: */
1.11 markus 684: if (buffer_len(&stdin_buffer) == 0) {
1.1 deraadt 685: packet_start(SSH_CMSG_EOF);
686: packet_send();
1.11 markus 687: }
688: } else if (escape_char == -1) {
1.13 markus 689: /*
690: * Normal successful read, and no escape character.
691: * Just append the data to buffer.
692: */
1.11 markus 693: buffer_append(&stdin_buffer, buf, len);
694: stdin_bytes += len;
695: } else {
1.13 markus 696: /*
697: * Normal, successful read. But we have an escape character
698: * and have to process the characters one by one.
699: */
1.31 markus 700: ret = process_escapes(&stdin_buffer, &stdout_buffer, &stderr_buffer, buf, len);
701: if (ret == -1)
702: return;
703: stdout_bytes += ret;
1.11 markus 704: }
705: }
706: }
707:
1.20 markus 708: void
1.11 markus 709: client_process_output(fd_set * writeset)
710: {
711: int len;
712: char buf[100];
1.1 deraadt 713:
1.11 markus 714: /* Write buffered output to stdout. */
715: if (FD_ISSET(fileno(stdout), writeset)) {
716: /* Write as much data as possible. */
717: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 718: buffer_len(&stdout_buffer));
1.11 markus 719: if (len <= 0) {
720: if (errno == EAGAIN)
721: len = 0;
722: else {
1.13 markus 723: /*
724: * An error or EOF was encountered. Put an
725: * error message to stderr buffer.
726: */
1.11 markus 727: snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
728: buffer_append(&stderr_buffer, buf, strlen(buf));
729: stderr_bytes += strlen(buf);
730: quit_pending = 1;
731: return;
732: }
733: }
734: /* Consume printed data from the buffer. */
735: buffer_consume(&stdout_buffer, len);
736: }
737: /* Write buffered output to stderr. */
738: if (FD_ISSET(fileno(stderr), writeset)) {
739: /* Write as much data as possible. */
740: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 741: buffer_len(&stderr_buffer));
1.11 markus 742: if (len <= 0) {
743: if (errno == EAGAIN)
744: len = 0;
745: else {
1.13 markus 746: /* EOF or error, but can't even print error message. */
1.11 markus 747: quit_pending = 1;
748: return;
749: }
750: }
751: /* Consume printed characters from the buffer. */
752: buffer_consume(&stderr_buffer, len);
753: }
1.1 deraadt 754: }
755:
1.13 markus 756: /*
1.15 markus 757: * Get packets from the connection input buffer, and process them as long as
758: * there are packets available.
759: *
760: * Any unknown packets received during the actual
761: * session cause the session to terminate. This is
762: * intended to make debugging easier since no
763: * confirmations are sent. Any compatible protocol
764: * extensions must be negotiated during the
765: * preparatory phase.
766: */
767:
1.20 markus 768: void
1.15 markus 769: client_process_buffered_input_packets()
770: {
1.36 markus 771: dispatch_run(DISPATCH_NONBLOCK, &quit_pending, NULL);
1.15 markus 772: }
773:
1.31 markus 774: /* scan buf[] for '~' before sending data to the peer */
1.30 markus 775:
776: int
1.31 markus 777: simple_escape_filter(Channel *c, char *buf, int len)
1.30 markus 778: {
1.31 markus 779: /* XXX we assume c->extended is writeable */
780: return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1.30 markus 781: }
782:
1.15 markus 783: /*
1.13 markus 784: * Implements the interactive session with the server. This is called after
785: * the user has been authenticated, and a command has been started on the
786: * remote host. If escape_char != -1, it is the character used as an escape
787: * character for terminating or suspending the session.
788: */
1.1 deraadt 789:
1.20 markus 790: int
1.30 markus 791: client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1.1 deraadt 792: {
1.11 markus 793: extern Options options;
794: double start_time, total_time;
795: int len;
796: char buf[100];
797:
798: debug("Entering interactive session.");
799:
800: start_time = get_current_time();
801:
802: /* Initialize variables. */
803: escape_pending = 0;
804: last_was_cr = 1;
805: exit_status = -1;
806: stdin_eof = 0;
807: buffer_high = 64 * 1024;
808: connection_in = packet_get_connection_in();
809: connection_out = packet_get_connection_out();
810: max_fd = connection_in;
811: if (connection_out > max_fd)
812: max_fd = connection_out;
813: stdin_bytes = 0;
814: stdout_bytes = 0;
815: stderr_bytes = 0;
816: quit_pending = 0;
817: escape_char = escape_char_arg;
818:
819: /* Initialize buffers. */
820: buffer_init(&stdin_buffer);
821: buffer_init(&stdout_buffer);
822: buffer_init(&stderr_buffer);
823:
1.15 markus 824: client_init_dispatch();
825:
1.11 markus 826: /* Set signal handlers to restore non-blocking mode. */
827: signal(SIGINT, signal_handler);
828: signal(SIGQUIT, signal_handler);
829: signal(SIGTERM, signal_handler);
830: signal(SIGPIPE, SIG_IGN);
831: if (have_pty)
832: signal(SIGWINCH, window_change_handler);
833:
834: if (have_pty)
835: enter_raw_mode();
836:
1.28 provos 837: /* Check if we should immediately send eof on stdin. */
1.17 markus 838: if (!compat20)
1.16 markus 839: client_check_initial_eof_on_stdin();
1.11 markus 840:
1.30 markus 841: if (compat20 && escape_char != -1)
842: channel_register_filter(ssh2_chan_id, simple_escape_filter);
843:
1.11 markus 844: /* Main loop of the client for the interactive session mode. */
845: while (!quit_pending) {
846: fd_set readset, writeset;
847:
1.13 markus 848: /* Process buffered packets sent by the server. */
1.11 markus 849: client_process_buffered_input_packets();
850:
1.16 markus 851: if (compat20 && !channel_still_open()) {
1.37 markus 852: debug2("!channel_still_open.");
1.16 markus 853: break;
854: }
855:
1.13 markus 856: /*
857: * Make packets of buffered stdin data, and buffer them for
858: * sending to the server.
859: */
1.17 markus 860: if (!compat20)
1.16 markus 861: client_make_packets_from_stdin_data();
1.11 markus 862:
1.13 markus 863: /*
864: * Make packets from buffered channel data, and buffer them
865: * for sending to the server.
866: */
1.11 markus 867: if (packet_not_very_much_data_to_write())
868: channel_output_poll();
869:
1.13 markus 870: /*
871: * Check if the window size has changed, and buffer a message
872: * about it to the server if so.
873: */
1.11 markus 874: client_check_window_change();
875:
876: if (quit_pending)
877: break;
878:
1.13 markus 879: /*
880: * Wait until we have something to do (something becomes
881: * available on one of the descriptors).
882: */
1.11 markus 883: client_wait_until_can_do_something(&readset, &writeset);
884:
885: if (quit_pending)
886: break;
887:
888: /* Do channel operations. */
889: channel_after_select(&readset, &writeset);
890:
1.17 markus 891: /* Buffer input from the connection. */
892: client_process_net_input(&readset);
893:
894: if (quit_pending)
895: break;
1.11 markus 896:
1.17 markus 897: if (!compat20) {
898: /* Buffer data from stdin */
899: client_process_input(&readset);
900: /*
901: * Process output to stdout and stderr. Output to
902: * the connection is processed elsewhere (above).
903: */
1.16 markus 904: client_process_output(&writeset);
1.17 markus 905: }
1.11 markus 906:
1.13 markus 907: /* Send as much buffered packet data as possible to the sender. */
1.11 markus 908: if (FD_ISSET(connection_out, &writeset))
909: packet_write_poll();
910: }
911:
912: /* Terminate the session. */
913:
914: /* Stop watching for window change. */
915: if (have_pty)
916: signal(SIGWINCH, SIG_DFL);
917:
918: /* Stop listening for connections. */
919: channel_stop_listening();
920:
1.13 markus 921: /*
922: * In interactive mode (with pseudo tty) display a message indicating
923: * that the connection has been closed.
924: */
1.11 markus 925: if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
926: snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
927: buffer_append(&stderr_buffer, buf, strlen(buf));
928: stderr_bytes += strlen(buf);
929: }
930: /* Output any buffered data for stdout. */
931: while (buffer_len(&stdout_buffer) > 0) {
932: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 933: buffer_len(&stdout_buffer));
1.11 markus 934: if (len <= 0) {
935: error("Write failed flushing stdout buffer.");
936: break;
937: }
938: buffer_consume(&stdout_buffer, len);
939: }
940:
941: /* Output any buffered data for stderr. */
942: while (buffer_len(&stderr_buffer) > 0) {
943: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 944: buffer_len(&stderr_buffer));
1.11 markus 945: if (len <= 0) {
946: error("Write failed flushing stderr buffer.");
947: break;
948: }
949: buffer_consume(&stderr_buffer, len);
950: }
951:
952: if (have_pty)
953: leave_raw_mode();
954:
955: /* Clear and free any buffers. */
956: memset(buf, 0, sizeof(buf));
957: buffer_free(&stdin_buffer);
958: buffer_free(&stdout_buffer);
959: buffer_free(&stderr_buffer);
960:
961: /* Report bytes transferred, and transfer rates. */
962: total_time = get_current_time() - start_time;
963: debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
964: stdin_bytes, stdout_bytes, stderr_bytes, total_time);
965: if (total_time > 0)
966: debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
967: stdin_bytes / total_time, stdout_bytes / total_time,
968: stderr_bytes / total_time);
969:
970: /* Return the exit status of the program. */
971: debug("Exit status %d", exit_status);
972: return exit_status;
1.15 markus 973: }
974:
975: /*********/
976:
977: void
1.36 markus 978: client_input_stdout_data(int type, int plen, void *ctxt)
1.15 markus 979: {
980: unsigned int data_len;
981: char *data = packet_get_string(&data_len);
982: packet_integrity_check(plen, 4 + data_len, type);
983: buffer_append(&stdout_buffer, data, data_len);
984: stdout_bytes += data_len;
985: memset(data, 0, data_len);
986: xfree(data);
987: }
988: void
1.36 markus 989: client_input_stderr_data(int type, int plen, void *ctxt)
1.15 markus 990: {
991: unsigned int data_len;
992: char *data = packet_get_string(&data_len);
993: packet_integrity_check(plen, 4 + data_len, type);
994: buffer_append(&stderr_buffer, data, data_len);
995: stdout_bytes += data_len;
996: memset(data, 0, data_len);
997: xfree(data);
998: }
999: void
1.36 markus 1000: client_input_exit_status(int type, int plen, void *ctxt)
1.15 markus 1001: {
1002: packet_integrity_check(plen, 4, type);
1003: exit_status = packet_get_int();
1004: /* Acknowledge the exit. */
1005: packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1006: packet_send();
1007: /*
1008: * Must wait for packet to be sent since we are
1009: * exiting the loop.
1010: */
1011: packet_write_wait();
1012: /* Flag that we want to exit. */
1013: quit_pending = 1;
1014: }
1015:
1.22 markus 1016: /* XXXX move to generic input handler */
1017: void
1.36 markus 1018: client_input_channel_open(int type, int plen, void *ctxt)
1.22 markus 1019: {
1020: Channel *c = NULL;
1021: char *ctype;
1022: int id;
1023: unsigned int len;
1024: int rchan;
1025: int rmaxpack;
1026: int rwindow;
1027:
1028: ctype = packet_get_string(&len);
1029: rchan = packet_get_int();
1030: rwindow = packet_get_int();
1031: rmaxpack = packet_get_int();
1032:
1.24 markus 1033: debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1.22 markus 1034: ctype, rchan, rwindow, rmaxpack);
1035:
1036: if (strcmp(ctype, "x11") == 0) {
1037: int sock;
1038: char *originator;
1039: int originator_port;
1040: originator = packet_get_string(NULL);
1.26 markus 1041: if (datafellows & SSH_BUG_X11FWD) {
1.37 markus 1042: debug2("buggy server: x11 request w/o originator_port");
1.25 markus 1043: originator_port = 0;
1.26 markus 1044: } else {
1045: originator_port = packet_get_int();
1.25 markus 1046: }
1.22 markus 1047: packet_done();
1048: /* XXX check permission */
1049: xfree(originator);
1050: /* XXX move to channels.c */
1051: sock = x11_connect_display();
1052: if (sock >= 0) {
1053: id = channel_new("x11", SSH_CHANNEL_X11_OPEN,
1.34 markus 1054: sock, sock, -1, CHAN_X11_WINDOW_DEFAULT,
1.38 ! markus 1055: CHAN_X11_PACKET_DEFAULT, 0, xstrdup("x11"), 1);
1.22 markus 1056: c = channel_lookup(id);
1057: }
1058: }
1059: /* XXX duplicate : */
1060: if (c != NULL) {
1061: debug("confirm %s", ctype);
1062: c->remote_id = rchan;
1063: c->remote_window = rwindow;
1064: c->remote_maxpacket = rmaxpack;
1065:
1066: packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1067: packet_put_int(c->remote_id);
1068: packet_put_int(c->self);
1069: packet_put_int(c->local_window);
1070: packet_put_int(c->local_maxpacket);
1071: packet_send();
1072: } else {
1073: debug("failure %s", ctype);
1074: packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1075: packet_put_int(rchan);
1076: packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1077: packet_put_cstring("bla bla");
1078: packet_put_cstring("");
1079: packet_send();
1080: }
1081: xfree(ctype);
1082: }
1083:
1.20 markus 1084: void
1.16 markus 1085: client_init_dispatch_20()
1086: {
1087: dispatch_init(&dispatch_protocol_error);
1088: dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1089: dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1090: dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1091: dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1.22 markus 1092: dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1.16 markus 1093: dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1094: dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1095: dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
1096: dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1097: }
1.20 markus 1098: void
1.15 markus 1099: client_init_dispatch_13()
1100: {
1101: dispatch_init(NULL);
1102: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1103: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1104: dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1105: dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1106: dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1107: dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1108: dispatch_set(SSH_SMSG_AGENT_OPEN, &auth_input_open_request);
1109: dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1110: dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1111: dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1112: dispatch_set(SSH_SMSG_X11_OPEN, &x11_input_open);
1113: }
1.20 markus 1114: void
1.15 markus 1115: client_init_dispatch_15()
1116: {
1117: client_init_dispatch_13();
1118: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1119: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1120: }
1.20 markus 1121: void
1.15 markus 1122: client_init_dispatch()
1123: {
1.16 markus 1124: if (compat20)
1125: client_init_dispatch_20();
1126: else if (compat13)
1.15 markus 1127: client_init_dispatch_13();
1128: else
1129: client_init_dispatch_15();
1.16 markus 1130: }
1131:
1132: void
1133: client_input_channel_req(int id, void *arg)
1134: {
1135: Channel *c = NULL;
1136: unsigned int len;
1137: int success = 0;
1138: int reply;
1139: char *rtype;
1140:
1141: rtype = packet_get_string(&len);
1142: reply = packet_get_char();
1143:
1.23 markus 1144: debug("client_input_channel_req: rtype %s reply %d", rtype, reply);
1.16 markus 1145:
1146: c = channel_lookup(id);
1147: if (c == NULL)
1.35 markus 1148: fatal("client_input_channel_req: channel %d: bad channel", id);
1.16 markus 1149:
1150: if (session_ident == -1) {
1151: error("client_input_channel_req: no channel %d", id);
1152: } else if (id != session_ident) {
1153: error("client_input_channel_req: bad channel %d != %d",
1154: id, session_ident);
1155: } else if (strcmp(rtype, "exit-status") == 0) {
1156: success = 1;
1157: exit_status = packet_get_int();
1.19 markus 1158: packet_done();
1.16 markus 1159: }
1160: if (reply) {
1161: packet_start(success ?
1162: SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1163: packet_put_int(c->remote_id);
1164: packet_send();
1165: }
1166: xfree(rtype);
1167: }
1168:
1169: void
1170: client_set_session_ident(int id)
1171: {
1.37 markus 1172: debug2("client_set_session_ident: id %d", id);
1.16 markus 1173: session_ident = id;
1174: channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
1175: client_input_channel_req, (void *)0);
1.1 deraadt 1176: }
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