]> andersk Git - openssh.git/blob - clientloop.c
- djm@cvs.openbsd.org 2008/06/12 21:06:25
[openssh.git] / clientloop.c
1 /* $OpenBSD: clientloop.c,v 1.199 2008/06/12 21:06:25 djm Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5  *                    All rights reserved
6  * The main loop for the interactive session (client side).
7  *
8  * As far as I am concerned, the code I have written for this software
9  * can be used freely for any purpose.  Any derived versions of this
10  * software must be clearly marked as such, and if the derived work is
11  * incompatible with the protocol description in the RFC file, it must be
12  * called by a name other than "ssh" or "Secure Shell".
13  *
14  *
15  * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
16  *
17  * Redistribution and use in source and binary forms, with or without
18  * modification, are permitted provided that the following conditions
19  * are met:
20  * 1. Redistributions of source code must retain the above copyright
21  *    notice, this list of conditions and the following disclaimer.
22  * 2. Redistributions in binary form must reproduce the above copyright
23  *    notice, this list of conditions and the following disclaimer in the
24  *    documentation and/or other materials provided with the distribution.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  *
37  *
38  * SSH2 support added by Markus Friedl.
39  * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
40  *
41  * Redistribution and use in source and binary forms, with or without
42  * modification, are permitted provided that the following conditions
43  * are met:
44  * 1. Redistributions of source code must retain the above copyright
45  *    notice, this list of conditions and the following disclaimer.
46  * 2. Redistributions in binary form must reproduce the above copyright
47  *    notice, this list of conditions and the following disclaimer in the
48  *    documentation and/or other materials provided with the distribution.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
51  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
52  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
53  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
54  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
55  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
56  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
57  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
58  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
59  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
60  */
61
62 #include "includes.h"
63
64 #include <sys/types.h>
65 #include <sys/ioctl.h>
66 #include <sys/param.h>
67 #ifdef HAVE_SYS_STAT_H
68 # include <sys/stat.h>
69 #endif
70 #ifdef HAVE_SYS_TIME_H
71 # include <sys/time.h>
72 #endif
73 #include <sys/socket.h>
74
75 #include <ctype.h>
76 #include <errno.h>
77 #ifdef HAVE_PATHS_H
78 #include <paths.h>
79 #endif
80 #include <signal.h>
81 #include <stdarg.h>
82 #include <stdio.h>
83 #include <stdlib.h>
84 #include <string.h>
85 #include <termios.h>
86 #include <pwd.h>
87 #include <unistd.h>
88
89 #include "openbsd-compat/sys-queue.h"
90 #include "xmalloc.h"
91 #include "ssh.h"
92 #include "ssh1.h"
93 #include "ssh2.h"
94 #include "packet.h"
95 #include "buffer.h"
96 #include "compat.h"
97 #include "channels.h"
98 #include "dispatch.h"
99 #include "key.h"
100 #include "cipher.h"
101 #include "kex.h"
102 #include "log.h"
103 #include "readconf.h"
104 #include "clientloop.h"
105 #include "sshconnect.h"
106 #include "authfd.h"
107 #include "atomicio.h"
108 #include "sshpty.h"
109 #include "misc.h"
110 #include "monitor_fdpass.h"
111 #include "match.h"
112 #include "msg.h"
113
114 /* import options */
115 extern Options options;
116
117 /* Flag indicating that stdin should be redirected from /dev/null. */
118 extern int stdin_null_flag;
119
120 /* Flag indicating that no shell has been requested */
121 extern int no_shell_flag;
122
123 /* Control socket */
124 extern int muxserver_sock;
125
126 /*
127  * Name of the host we are connecting to.  This is the name given on the
128  * command line, or the HostName specified for the user-supplied name in a
129  * configuration file.
130  */
131 extern char *host;
132
133 /*
134  * Flag to indicate that we have received a window change signal which has
135  * not yet been processed.  This will cause a message indicating the new
136  * window size to be sent to the server a little later.  This is volatile
137  * because this is updated in a signal handler.
138  */
139 static volatile sig_atomic_t received_window_change_signal = 0;
140 static volatile sig_atomic_t received_signal = 0;
141
142 /* Flag indicating whether the user's terminal is in non-blocking mode. */
143 static int in_non_blocking_mode = 0;
144
145 /* Common data for the client loop code. */
146 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
147 static int escape_char1;        /* Escape character. (proto1 only) */
148 static int escape_pending1;     /* Last character was an escape (proto1 only) */
149 static int last_was_cr;         /* Last character was a newline. */
150 static int exit_status;         /* Used to store the command exit status. */
151 static int stdin_eof;           /* EOF has been encountered on stderr. */
152 static Buffer stdin_buffer;     /* Buffer for stdin data. */
153 static Buffer stdout_buffer;    /* Buffer for stdout data. */
154 static Buffer stderr_buffer;    /* Buffer for stderr data. */
155 static u_long stdin_bytes, stdout_bytes, stderr_bytes;
156 static u_int buffer_high;/* Soft max buffer size. */
157 static int connection_in;       /* Connection to server (input). */
158 static int connection_out;      /* Connection to server (output). */
159 static int need_rekeying;       /* Set to non-zero if rekeying is requested. */
160 static int session_closed = 0;  /* In SSH2: login session closed. */
161
162 static void client_init_dispatch(void);
163 int     session_ident = -1;
164
165 /* Track escape per proto2 channel */
166 struct escape_filter_ctx {
167         int escape_pending;
168         int escape_char;
169 };
170
171 /* Context for channel confirmation replies */
172 struct channel_reply_ctx {
173         const char *request_type;
174         int id, do_close;
175 };
176
177 /* Global request success/failure callbacks */
178 struct global_confirm {
179         TAILQ_ENTRY(global_confirm) entry;
180         global_confirm_cb *cb;
181         void *ctx;
182         int ref_count;
183 };
184 TAILQ_HEAD(global_confirms, global_confirm);
185 static struct global_confirms global_confirms =
186     TAILQ_HEAD_INITIALIZER(global_confirms);
187
188 /*XXX*/
189 extern Kex *xxx_kex;
190
191 void ssh_process_session2_setup(int, int, int, Buffer *);
192
193 /* Restores stdin to blocking mode. */
194
195 static void
196 leave_non_blocking(void)
197 {
198         if (in_non_blocking_mode) {
199                 unset_nonblock(fileno(stdin));
200                 in_non_blocking_mode = 0;
201         }
202 }
203
204 /* Puts stdin terminal in non-blocking mode. */
205
206 static void
207 enter_non_blocking(void)
208 {
209         in_non_blocking_mode = 1;
210         set_nonblock(fileno(stdin));
211 }
212
213 /*
214  * Signal handler for the window change signal (SIGWINCH).  This just sets a
215  * flag indicating that the window has changed.
216  */
217 /*ARGSUSED */
218 static void
219 window_change_handler(int sig)
220 {
221         received_window_change_signal = 1;
222         signal(SIGWINCH, window_change_handler);
223 }
224
225 /*
226  * Signal handler for signals that cause the program to terminate.  These
227  * signals must be trapped to restore terminal modes.
228  */
229 /*ARGSUSED */
230 static void
231 signal_handler(int sig)
232 {
233         received_signal = sig;
234         quit_pending = 1;
235 }
236
237 /*
238  * Returns current time in seconds from Jan 1, 1970 with the maximum
239  * available resolution.
240  */
241
242 static double
243 get_current_time(void)
244 {
245         struct timeval tv;
246         gettimeofday(&tv, NULL);
247         return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
248 }
249
250 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
251 void
252 client_x11_get_proto(const char *display, const char *xauth_path,
253     u_int trusted, char **_proto, char **_data)
254 {
255         char cmd[1024];
256         char line[512];
257         char xdisplay[512];
258         static char proto[512], data[512];
259         FILE *f;
260         int got_data = 0, generated = 0, do_unlink = 0, i;
261         char *xauthdir, *xauthfile;
262         struct stat st;
263
264         xauthdir = xauthfile = NULL;
265         *_proto = proto;
266         *_data = data;
267         proto[0] = data[0] = '\0';
268
269         if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) {
270                 debug("No xauth program.");
271         } else {
272                 if (display == NULL) {
273                         debug("x11_get_proto: DISPLAY not set");
274                         return;
275                 }
276                 /*
277                  * Handle FamilyLocal case where $DISPLAY does
278                  * not match an authorization entry.  For this we
279                  * just try "xauth list unix:displaynum.screennum".
280                  * XXX: "localhost" match to determine FamilyLocal
281                  *      is not perfect.
282                  */
283                 if (strncmp(display, "localhost:", 10) == 0) {
284                         snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
285                             display + 10);
286                         display = xdisplay;
287                 }
288                 if (trusted == 0) {
289                         xauthdir = xmalloc(MAXPATHLEN);
290                         xauthfile = xmalloc(MAXPATHLEN);
291                         strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
292                         if (mkdtemp(xauthdir) != NULL) {
293                                 do_unlink = 1;
294                                 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile",
295                                     xauthdir);
296                                 snprintf(cmd, sizeof(cmd),
297                                     "%s -f %s generate %s " SSH_X11_PROTO
298                                     " untrusted timeout 1200 2>" _PATH_DEVNULL,
299                                     xauth_path, xauthfile, display);
300                                 debug2("x11_get_proto: %s", cmd);
301                                 if (system(cmd) == 0)
302                                         generated = 1;
303                         }
304                 }
305
306                 /*
307                  * When in untrusted mode, we read the cookie only if it was
308                  * successfully generated as an untrusted one in the step
309                  * above.
310                  */
311                 if (trusted || generated) {
312                         snprintf(cmd, sizeof(cmd),
313                             "%s %s%s list %s 2>" _PATH_DEVNULL,
314                             xauth_path,
315                             generated ? "-f " : "" ,
316                             generated ? xauthfile : "",
317                             display);
318                         debug2("x11_get_proto: %s", cmd);
319                         f = popen(cmd, "r");
320                         if (f && fgets(line, sizeof(line), f) &&
321                             sscanf(line, "%*s %511s %511s", proto, data) == 2)
322                                 got_data = 1;
323                         if (f)
324                                 pclose(f);
325                 } else
326                         error("Warning: untrusted X11 forwarding setup failed: "
327                             "xauth key data not generated");
328         }
329
330         if (do_unlink) {
331                 unlink(xauthfile);
332                 rmdir(xauthdir);
333         }
334         if (xauthdir)
335                 xfree(xauthdir);
336         if (xauthfile)
337                 xfree(xauthfile);
338
339         /*
340          * If we didn't get authentication data, just make up some
341          * data.  The forwarding code will check the validity of the
342          * response anyway, and substitute this data.  The X11
343          * server, however, will ignore this fake data and use
344          * whatever authentication mechanisms it was using otherwise
345          * for the local connection.
346          */
347         if (!got_data) {
348                 u_int32_t rnd = 0;
349
350                 logit("Warning: No xauth data; "
351                     "using fake authentication data for X11 forwarding.");
352                 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
353                 for (i = 0; i < 16; i++) {
354                         if (i % 4 == 0)
355                                 rnd = arc4random();
356                         snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
357                             rnd & 0xff);
358                         rnd >>= 8;
359                 }
360         }
361 }
362
363 /*
364  * This is called when the interactive is entered.  This checks if there is
365  * an EOF coming on stdin.  We must check this explicitly, as select() does
366  * not appear to wake up when redirecting from /dev/null.
367  */
368
369 static void
370 client_check_initial_eof_on_stdin(void)
371 {
372         int len;
373         char buf[1];
374
375         /*
376          * If standard input is to be "redirected from /dev/null", we simply
377          * mark that we have seen an EOF and send an EOF message to the
378          * server. Otherwise, we try to read a single character; it appears
379          * that for some files, such /dev/null, select() never wakes up for
380          * read for this descriptor, which means that we never get EOF.  This
381          * way we will get the EOF if stdin comes from /dev/null or similar.
382          */
383         if (stdin_null_flag) {
384                 /* Fake EOF on stdin. */
385                 debug("Sending eof.");
386                 stdin_eof = 1;
387                 packet_start(SSH_CMSG_EOF);
388                 packet_send();
389         } else {
390                 enter_non_blocking();
391
392                 /* Check for immediate EOF on stdin. */
393                 len = read(fileno(stdin), buf, 1);
394                 if (len == 0) {
395                         /*
396                          * EOF.  Record that we have seen it and send
397                          * EOF to server.
398                          */
399                         debug("Sending eof.");
400                         stdin_eof = 1;
401                         packet_start(SSH_CMSG_EOF);
402                         packet_send();
403                 } else if (len > 0) {
404                         /*
405                          * Got data.  We must store the data in the buffer,
406                          * and also process it as an escape character if
407                          * appropriate.
408                          */
409                         if ((u_char) buf[0] == escape_char1)
410                                 escape_pending1 = 1;
411                         else
412                                 buffer_append(&stdin_buffer, buf, 1);
413                 }
414                 leave_non_blocking();
415         }
416 }
417
418
419 /*
420  * Make packets from buffered stdin data, and buffer them for sending to the
421  * connection.
422  */
423
424 static void
425 client_make_packets_from_stdin_data(void)
426 {
427         u_int len;
428
429         /* Send buffered stdin data to the server. */
430         while (buffer_len(&stdin_buffer) > 0 &&
431             packet_not_very_much_data_to_write()) {
432                 len = buffer_len(&stdin_buffer);
433                 /* Keep the packets at reasonable size. */
434                 if (len > packet_get_maxsize())
435                         len = packet_get_maxsize();
436                 packet_start(SSH_CMSG_STDIN_DATA);
437                 packet_put_string(buffer_ptr(&stdin_buffer), len);
438                 packet_send();
439                 buffer_consume(&stdin_buffer, len);
440                 stdin_bytes += len;
441                 /* If we have a pending EOF, send it now. */
442                 if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
443                         packet_start(SSH_CMSG_EOF);
444                         packet_send();
445                 }
446         }
447 }
448
449 /*
450  * Checks if the client window has changed, and sends a packet about it to
451  * the server if so.  The actual change is detected elsewhere (by a software
452  * interrupt on Unix); this just checks the flag and sends a message if
453  * appropriate.
454  */
455
456 static void
457 client_check_window_change(void)
458 {
459         struct winsize ws;
460
461         if (! received_window_change_signal)
462                 return;
463         /** XXX race */
464         received_window_change_signal = 0;
465
466         debug2("client_check_window_change: changed");
467
468         if (compat20) {
469                 channel_send_window_changes();
470         } else {
471                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
472                         return;
473                 packet_start(SSH_CMSG_WINDOW_SIZE);
474                 packet_put_int((u_int)ws.ws_row);
475                 packet_put_int((u_int)ws.ws_col);
476                 packet_put_int((u_int)ws.ws_xpixel);
477                 packet_put_int((u_int)ws.ws_ypixel);
478                 packet_send();
479         }
480 }
481
482 static void
483 client_global_request_reply(int type, u_int32_t seq, void *ctxt)
484 {
485         struct global_confirm *gc;
486
487         if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
488                 return;
489         if (gc->cb != NULL)
490                 gc->cb(type, seq, gc->ctx);
491         if (--gc->ref_count <= 0) {
492                 TAILQ_REMOVE(&global_confirms, gc, entry);
493                 bzero(gc, sizeof(*gc));
494                 xfree(gc);
495         }
496
497         keep_alive_timeouts = 0;
498 }
499
500 static void
501 server_alive_check(void)
502 {
503         if (++keep_alive_timeouts > options.server_alive_count_max) {
504                 logit("Timeout, server not responding.");
505                 cleanup_exit(255);
506         }
507         packet_start(SSH2_MSG_GLOBAL_REQUEST);
508         packet_put_cstring("keepalive@openssh.com");
509         packet_put_char(1);     /* boolean: want reply */
510         packet_send();
511         /* Insert an empty placeholder to maintain ordering */
512         client_register_global_confirm(NULL, NULL);
513 }
514
515 /*
516  * Waits until the client can do something (some data becomes available on
517  * one of the file descriptors).
518  */
519 static void
520 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
521     int *maxfdp, u_int *nallocp, int rekeying)
522 {
523         struct timeval tv, *tvp;
524         int ret;
525
526         /* Add any selections by the channel mechanism. */
527         channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying);
528
529         if (!compat20) {
530                 /* Read from the connection, unless our buffers are full. */
531                 if (buffer_len(&stdout_buffer) < buffer_high &&
532                     buffer_len(&stderr_buffer) < buffer_high &&
533                     channel_not_very_much_buffered_data())
534                         FD_SET(connection_in, *readsetp);
535                 /*
536                  * Read from stdin, unless we have seen EOF or have very much
537                  * buffered data to send to the server.
538                  */
539                 if (!stdin_eof && packet_not_very_much_data_to_write())
540                         FD_SET(fileno(stdin), *readsetp);
541
542                 /* Select stdout/stderr if have data in buffer. */
543                 if (buffer_len(&stdout_buffer) > 0)
544                         FD_SET(fileno(stdout), *writesetp);
545                 if (buffer_len(&stderr_buffer) > 0)
546                         FD_SET(fileno(stderr), *writesetp);
547         } else {
548                 /* channel_prepare_select could have closed the last channel */
549                 if (session_closed && !channel_still_open() &&
550                     !packet_have_data_to_write()) {
551                         /* clear mask since we did not call select() */
552                         memset(*readsetp, 0, *nallocp);
553                         memset(*writesetp, 0, *nallocp);
554                         return;
555                 } else {
556                         FD_SET(connection_in, *readsetp);
557                 }
558         }
559
560         /* Select server connection if have data to write to the server. */
561         if (packet_have_data_to_write())
562                 FD_SET(connection_out, *writesetp);
563
564         if (muxserver_sock != -1)
565                 FD_SET(muxserver_sock, *readsetp);
566
567         /*
568          * Wait for something to happen.  This will suspend the process until
569          * some selected descriptor can be read, written, or has some other
570          * event pending.
571          */
572
573         if (options.server_alive_interval == 0 || !compat20)
574                 tvp = NULL;
575         else {
576                 tv.tv_sec = options.server_alive_interval;
577                 tv.tv_usec = 0;
578                 tvp = &tv;
579         }
580         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
581         if (ret < 0) {
582                 char buf[100];
583
584                 /*
585                  * We have to clear the select masks, because we return.
586                  * We have to return, because the mainloop checks for the flags
587                  * set by the signal handlers.
588                  */
589                 memset(*readsetp, 0, *nallocp);
590                 memset(*writesetp, 0, *nallocp);
591
592                 if (errno == EINTR)
593                         return;
594                 /* Note: we might still have data in the buffers. */
595                 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
596                 buffer_append(&stderr_buffer, buf, strlen(buf));
597                 quit_pending = 1;
598         } else if (ret == 0)
599                 server_alive_check();
600 }
601
602 static void
603 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
604 {
605         /* Flush stdout and stderr buffers. */
606         if (buffer_len(bout) > 0)
607                 atomicio(vwrite, fileno(stdout), buffer_ptr(bout),
608                     buffer_len(bout));
609         if (buffer_len(berr) > 0)
610                 atomicio(vwrite, fileno(stderr), buffer_ptr(berr),
611                     buffer_len(berr));
612
613         leave_raw_mode();
614
615         /*
616          * Free (and clear) the buffer to reduce the amount of data that gets
617          * written to swap.
618          */
619         buffer_free(bin);
620         buffer_free(bout);
621         buffer_free(berr);
622
623         /* Send the suspend signal to the program itself. */
624         kill(getpid(), SIGTSTP);
625
626         /* Reset window sizes in case they have changed */
627         received_window_change_signal = 1;
628
629         /* OK, we have been continued by the user. Reinitialize buffers. */
630         buffer_init(bin);
631         buffer_init(bout);
632         buffer_init(berr);
633
634         enter_raw_mode();
635 }
636
637 static void
638 client_process_net_input(fd_set *readset)
639 {
640         int len;
641         char buf[8192];
642
643         /*
644          * Read input from the server, and add any such data to the buffer of
645          * the packet subsystem.
646          */
647         if (FD_ISSET(connection_in, readset)) {
648                 /* Read as much as possible. */
649                 len = read(connection_in, buf, sizeof(buf));
650                 if (len == 0) {
651                         /*
652                          * Received EOF.  The remote host has closed the
653                          * connection.
654                          */
655                         snprintf(buf, sizeof buf,
656                             "Connection to %.300s closed by remote host.\r\n",
657                             host);
658                         buffer_append(&stderr_buffer, buf, strlen(buf));
659                         quit_pending = 1;
660                         return;
661                 }
662                 /*
663                  * There is a kernel bug on Solaris that causes select to
664                  * sometimes wake up even though there is no data available.
665                  */
666                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
667                         len = 0;
668
669                 if (len < 0) {
670                         /*
671                          * An error has encountered.  Perhaps there is a
672                          * network problem.
673                          */
674                         snprintf(buf, sizeof buf,
675                             "Read from remote host %.300s: %.100s\r\n",
676                             host, strerror(errno));
677                         buffer_append(&stderr_buffer, buf, strlen(buf));
678                         quit_pending = 1;
679                         return;
680                 }
681                 packet_process_incoming(buf, len);
682         }
683 }
684
685 static void
686 client_status_confirm(int type, Channel *c, void *ctx)
687 {
688         struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
689         char errmsg[256];
690         int tochan;
691
692         /* XXX supress on mux _client_ quietmode */
693         tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
694             c->ctl_fd != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
695
696         if (type == SSH2_MSG_CHANNEL_SUCCESS) {
697                 debug2("%s request accepted on channel %d",
698                     cr->request_type, c->self);
699         } else if (type == SSH2_MSG_CHANNEL_FAILURE) {
700                 if (tochan) {
701                         snprintf(errmsg, sizeof(errmsg),
702                             "%s request failed\r\n", cr->request_type);
703                 } else {
704                         snprintf(errmsg, sizeof(errmsg),
705                             "%s request failed on channel %d",
706                             cr->request_type, c->self);
707                 }
708                 /* If error occurred on primary session channel, then exit */
709                 if (cr->do_close && c->self == session_ident)
710                         fatal("%s", errmsg);
711                 /* If error occurred on mux client, append to their stderr */
712                 if (tochan)
713                         buffer_append(&c->extended, errmsg, strlen(errmsg));
714                 else
715                         error("%s", errmsg);
716                 if (cr->do_close) {
717                         chan_read_failed(c);
718                         chan_write_failed(c);
719                 }
720         }
721         xfree(cr);
722 }
723
724 static void
725 client_abandon_status_confirm(Channel *c, void *ctx)
726 {
727         xfree(ctx);
728 }
729
730 static void
731 client_expect_confirm(int id, const char *request, int do_close)
732 {
733         struct channel_reply_ctx *cr = xmalloc(sizeof(*cr));
734
735         cr->request_type = request;
736         cr->do_close = do_close;
737
738         channel_register_status_confirm(id, client_status_confirm,
739             client_abandon_status_confirm, cr);
740 }
741
742 void
743 client_register_global_confirm(global_confirm_cb *cb, void *ctx)
744 {
745         struct global_confirm *gc, *first_gc;
746
747         /* Coalesce identical callbacks */
748         first_gc = TAILQ_LAST(&global_confirms, global_confirms);
749         if (first_gc && first_gc->cb == cb && first_gc->ctx == ctx) {
750                 if (++first_gc->ref_count >= INT_MAX)
751                         fatal("%s: first_gc->ref_count = %d",
752                             __func__, first_gc->ref_count);
753                 return;
754         }
755
756         gc = xmalloc(sizeof(*gc));
757         gc->cb = cb;
758         gc->ctx = ctx;
759         gc->ref_count = 1;
760         TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
761 }
762
763 static void
764 process_cmdline(void)
765 {
766         void (*handler)(int);
767         char *s, *cmd, *cancel_host;
768         int delete = 0;
769         int local = 0;
770         u_short cancel_port;
771         Forward fwd;
772
773         bzero(&fwd, sizeof(fwd));
774         fwd.listen_host = fwd.connect_host = NULL;
775
776         leave_raw_mode();
777         handler = signal(SIGINT, SIG_IGN);
778         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
779         if (s == NULL)
780                 goto out;
781         while (isspace(*s))
782                 s++;
783         if (*s == '-')
784                 s++;    /* Skip cmdline '-', if any */
785         if (*s == '\0')
786                 goto out;
787
788         if (*s == 'h' || *s == 'H' || *s == '?') {
789                 logit("Commands:");
790                 logit("      -L[bind_address:]port:host:hostport    "
791                     "Request local forward");
792                 logit("      -R[bind_address:]port:host:hostport    "
793                     "Request remote forward");
794                 logit("      -KR[bind_address:]port                 "
795                     "Cancel remote forward");
796                 if (!options.permit_local_command)
797                         goto out;
798                 logit("      !args                                  "
799                     "Execute local command");
800                 goto out;
801         }
802
803         if (*s == '!' && options.permit_local_command) {
804                 s++;
805                 ssh_local_cmd(s);
806                 goto out;
807         }
808
809         if (*s == 'K') {
810                 delete = 1;
811                 s++;
812         }
813         if (*s != 'L' && *s != 'R') {
814                 logit("Invalid command.");
815                 goto out;
816         }
817         if (*s == 'L')
818                 local = 1;
819         if (local && delete) {
820                 logit("Not supported.");
821                 goto out;
822         }
823         if ((!local || delete) && !compat20) {
824                 logit("Not supported for SSH protocol version 1.");
825                 goto out;
826         }
827
828         while (isspace(*++s))
829                 ;
830
831         if (delete) {
832                 cancel_port = 0;
833                 cancel_host = hpdelim(&s);      /* may be NULL */
834                 if (s != NULL) {
835                         cancel_port = a2port(s);
836                         cancel_host = cleanhostname(cancel_host);
837                 } else {
838                         cancel_port = a2port(cancel_host);
839                         cancel_host = NULL;
840                 }
841                 if (cancel_port == 0) {
842                         logit("Bad forwarding close port");
843                         goto out;
844                 }
845                 channel_request_rforward_cancel(cancel_host, cancel_port);
846         } else {
847                 if (!parse_forward(&fwd, s)) {
848                         logit("Bad forwarding specification.");
849                         goto out;
850                 }
851                 if (local) {
852                         if (channel_setup_local_fwd_listener(fwd.listen_host,
853                             fwd.listen_port, fwd.connect_host,
854                             fwd.connect_port, options.gateway_ports) < 0) {
855                                 logit("Port forwarding failed.");
856                                 goto out;
857                         }
858                 } else {
859                         if (channel_request_remote_forwarding(fwd.listen_host,
860                             fwd.listen_port, fwd.connect_host,
861                             fwd.connect_port) < 0) {
862                                 logit("Port forwarding failed.");
863                                 goto out;
864                         }
865                 }
866
867                 logit("Forwarding port.");
868         }
869
870 out:
871         signal(SIGINT, handler);
872         enter_raw_mode();
873         if (cmd)
874                 xfree(cmd);
875         if (fwd.listen_host != NULL)
876                 xfree(fwd.listen_host);
877         if (fwd.connect_host != NULL)
878                 xfree(fwd.connect_host);
879 }
880
881 /* 
882  * Process the characters one by one, call with c==NULL for proto1 case.
883  */
884 static int
885 process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
886     char *buf, int len)
887 {
888         char string[1024];
889         pid_t pid;
890         int bytes = 0;
891         u_int i;
892         u_char ch;
893         char *s;
894         int *escape_pendingp, escape_char;
895         struct escape_filter_ctx *efc;
896
897         if (c == NULL) {
898                 escape_pendingp = &escape_pending1;
899                 escape_char = escape_char1;
900         } else {
901                 if (c->filter_ctx == NULL)
902                         return 0;
903                 efc = (struct escape_filter_ctx *)c->filter_ctx;
904                 escape_pendingp = &efc->escape_pending;
905                 escape_char = efc->escape_char;
906         }
907         
908         if (len <= 0)
909                 return (0);
910
911         for (i = 0; i < (u_int)len; i++) {
912                 /* Get one character at a time. */
913                 ch = buf[i];
914
915                 if (*escape_pendingp) {
916                         /* We have previously seen an escape character. */
917                         /* Clear the flag now. */
918                         *escape_pendingp = 0;
919
920                         /* Process the escaped character. */
921                         switch (ch) {
922                         case '.':
923                                 /* Terminate the connection. */
924                                 snprintf(string, sizeof string, "%c.\r\n",
925                                     escape_char);
926                                 buffer_append(berr, string, strlen(string));
927
928                                 if (c && c->ctl_fd != -1) {
929                                         chan_read_failed(c);
930                                         chan_write_failed(c);
931                                         return 0;
932                                 } else
933                                         quit_pending = 1;
934                                 return -1;
935
936                         case 'Z' - 64:
937                                 /* XXX support this for mux clients */
938                                 if (c && c->ctl_fd != -1) {
939  noescape:
940                                         snprintf(string, sizeof string,
941                                             "%c%c escape not available to "
942                                             "multiplexed sessions\r\n",
943                                             escape_char, ch);
944                                         buffer_append(berr, string,
945                                             strlen(string));
946                                         continue;
947                                 }
948                                 /* Suspend the program. Inform the user */
949                                 snprintf(string, sizeof string,
950                                     "%c^Z [suspend ssh]\r\n", escape_char);
951                                 buffer_append(berr, string, strlen(string));
952
953                                 /* Restore terminal modes and suspend. */
954                                 client_suspend_self(bin, bout, berr);
955
956                                 /* We have been continued. */
957                                 continue;
958
959                         case 'B':
960                                 if (compat20) {
961                                         snprintf(string, sizeof string,
962                                             "%cB\r\n", escape_char);
963                                         buffer_append(berr, string,
964                                             strlen(string));
965                                         channel_request_start(session_ident,
966                                             "break", 0);
967                                         packet_put_int(1000);
968                                         packet_send();
969                                 }
970                                 continue;
971
972                         case 'R':
973                                 if (compat20) {
974                                         if (datafellows & SSH_BUG_NOREKEY)
975                                                 logit("Server does not "
976                                                     "support re-keying");
977                                         else
978                                                 need_rekeying = 1;
979                                 }
980                                 continue;
981
982                         case '&':
983                                 if (c && c->ctl_fd != -1)
984                                         goto noescape;
985                                 /*
986                                  * Detach the program (continue to serve
987                                  * connections, but put in background and no
988                                  * more new connections).
989                                  */
990                                 /* Restore tty modes. */
991                                 leave_raw_mode();
992
993                                 /* Stop listening for new connections. */
994                                 channel_stop_listening();
995
996                                 snprintf(string, sizeof string,
997                                     "%c& [backgrounded]\n", escape_char);
998                                 buffer_append(berr, string, strlen(string));
999
1000                                 /* Fork into background. */
1001                                 pid = fork();
1002                                 if (pid < 0) {
1003                                         error("fork: %.100s", strerror(errno));
1004                                         continue;
1005                                 }
1006                                 if (pid != 0) { /* This is the parent. */
1007                                         /* The parent just exits. */
1008                                         exit(0);
1009                                 }
1010                                 /* The child continues serving connections. */
1011                                 if (compat20) {
1012                                         buffer_append(bin, "\004", 1);
1013                                         /* fake EOF on stdin */
1014                                         return -1;
1015                                 } else if (!stdin_eof) {
1016                                         /*
1017                                          * Sending SSH_CMSG_EOF alone does not
1018                                          * always appear to be enough.  So we
1019                                          * try to send an EOF character first.
1020                                          */
1021                                         packet_start(SSH_CMSG_STDIN_DATA);
1022                                         packet_put_string("\004", 1);
1023                                         packet_send();
1024                                         /* Close stdin. */
1025                                         stdin_eof = 1;
1026                                         if (buffer_len(bin) == 0) {
1027                                                 packet_start(SSH_CMSG_EOF);
1028                                                 packet_send();
1029                                         }
1030                                 }
1031                                 continue;
1032
1033                         case '?':
1034                                 if (c && c->ctl_fd != -1) {
1035                                         snprintf(string, sizeof string,
1036 "%c?\r\n\
1037 Supported escape sequences:\r\n\
1038   %c.  - terminate session\r\n\
1039   %cB  - send a BREAK to the remote system\r\n\
1040   %cC  - open a command line\r\n\
1041   %cR  - Request rekey (SSH protocol 2 only)\r\n\
1042   %c#  - list forwarded connections\r\n\
1043   %c?  - this message\r\n\
1044   %c%c  - send the escape character by typing it twice\r\n\
1045 (Note that escapes are only recognized immediately after newline.)\r\n",
1046                                             escape_char, escape_char,
1047                                             escape_char, escape_char,
1048                                             escape_char, escape_char,
1049                                             escape_char, escape_char,
1050                                             escape_char);
1051                                 } else {
1052                                         snprintf(string, sizeof string,
1053 "%c?\r\n\
1054 Supported escape sequences:\r\n\
1055   %c.  - terminate connection (and any multiplexed sessions)\r\n\
1056   %cB  - send a BREAK to the remote system\r\n\
1057   %cC  - open a command line\r\n\
1058   %cR  - Request rekey (SSH protocol 2 only)\r\n\
1059   %c^Z - suspend ssh\r\n\
1060   %c#  - list forwarded connections\r\n\
1061   %c&  - background ssh (when waiting for connections to terminate)\r\n\
1062   %c?  - this message\r\n\
1063   %c%c  - send the escape character by typing it twice\r\n\
1064 (Note that escapes are only recognized immediately after newline.)\r\n",
1065                                             escape_char, escape_char,
1066                                             escape_char, escape_char,
1067                                             escape_char, escape_char,
1068                                             escape_char, escape_char,
1069                                             escape_char, escape_char,
1070                                             escape_char);
1071                                 }
1072                                 buffer_append(berr, string, strlen(string));
1073                                 continue;
1074
1075                         case '#':
1076                                 snprintf(string, sizeof string, "%c#\r\n",
1077                                     escape_char);
1078                                 buffer_append(berr, string, strlen(string));
1079                                 s = channel_open_message();
1080                                 buffer_append(berr, s, strlen(s));
1081                                 xfree(s);
1082                                 continue;
1083
1084                         case 'C':
1085                                 process_cmdline();
1086                                 continue;
1087
1088                         default:
1089                                 if (ch != escape_char) {
1090                                         buffer_put_char(bin, escape_char);
1091                                         bytes++;
1092                                 }
1093                                 /* Escaped characters fall through here */
1094                                 break;
1095                         }
1096                 } else {
1097                         /*
1098                          * The previous character was not an escape char.
1099                          * Check if this is an escape.
1100                          */
1101                         if (last_was_cr && ch == escape_char) {
1102                                 /*
1103                                  * It is. Set the flag and continue to
1104                                  * next character.
1105                                  */
1106                                 *escape_pendingp = 1;
1107                                 continue;
1108                         }
1109                 }
1110
1111                 /*
1112                  * Normal character.  Record whether it was a newline,
1113                  * and append it to the buffer.
1114                  */
1115                 last_was_cr = (ch == '\r' || ch == '\n');
1116                 buffer_put_char(bin, ch);
1117                 bytes++;
1118         }
1119         return bytes;
1120 }
1121
1122 static void
1123 client_process_input(fd_set *readset)
1124 {
1125         int len;
1126         char buf[8192];
1127
1128         /* Read input from stdin. */
1129         if (FD_ISSET(fileno(stdin), readset)) {
1130                 /* Read as much as possible. */
1131                 len = read(fileno(stdin), buf, sizeof(buf));
1132                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
1133                         return;         /* we'll try again later */
1134                 if (len <= 0) {
1135                         /*
1136                          * Received EOF or error.  They are treated
1137                          * similarly, except that an error message is printed
1138                          * if it was an error condition.
1139                          */
1140                         if (len < 0) {
1141                                 snprintf(buf, sizeof buf, "read: %.100s\r\n",
1142                                     strerror(errno));
1143                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1144                         }
1145                         /* Mark that we have seen EOF. */
1146                         stdin_eof = 1;
1147                         /*
1148                          * Send an EOF message to the server unless there is
1149                          * data in the buffer.  If there is data in the
1150                          * buffer, no message will be sent now.  Code
1151                          * elsewhere will send the EOF when the buffer
1152                          * becomes empty if stdin_eof is set.
1153                          */
1154                         if (buffer_len(&stdin_buffer) == 0) {
1155                                 packet_start(SSH_CMSG_EOF);
1156                                 packet_send();
1157                         }
1158                 } else if (escape_char1 == SSH_ESCAPECHAR_NONE) {
1159                         /*
1160                          * Normal successful read, and no escape character.
1161                          * Just append the data to buffer.
1162                          */
1163                         buffer_append(&stdin_buffer, buf, len);
1164                 } else {
1165                         /*
1166                          * Normal, successful read.  But we have an escape
1167                          * character and have to process the characters one
1168                          * by one.
1169                          */
1170                         if (process_escapes(NULL, &stdin_buffer,
1171                             &stdout_buffer, &stderr_buffer, buf, len) == -1)
1172                                 return;
1173                 }
1174         }
1175 }
1176
1177 static void
1178 client_process_output(fd_set *writeset)
1179 {
1180         int len;
1181         char buf[100];
1182
1183         /* Write buffered output to stdout. */
1184         if (FD_ISSET(fileno(stdout), writeset)) {
1185                 /* Write as much data as possible. */
1186                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1187                     buffer_len(&stdout_buffer));
1188                 if (len <= 0) {
1189                         if (errno == EINTR || errno == EAGAIN)
1190                                 len = 0;
1191                         else {
1192                                 /*
1193                                  * An error or EOF was encountered.  Put an
1194                                  * error message to stderr buffer.
1195                                  */
1196                                 snprintf(buf, sizeof buf,
1197                                     "write stdout: %.50s\r\n", strerror(errno));
1198                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1199                                 quit_pending = 1;
1200                                 return;
1201                         }
1202                 }
1203                 /* Consume printed data from the buffer. */
1204                 buffer_consume(&stdout_buffer, len);
1205                 stdout_bytes += len;
1206         }
1207         /* Write buffered output to stderr. */
1208         if (FD_ISSET(fileno(stderr), writeset)) {
1209                 /* Write as much data as possible. */
1210                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1211                     buffer_len(&stderr_buffer));
1212                 if (len <= 0) {
1213                         if (errno == EINTR || errno == EAGAIN)
1214                                 len = 0;
1215                         else {
1216                                 /*
1217                                  * EOF or error, but can't even print
1218                                  * error message.
1219                                  */
1220                                 quit_pending = 1;
1221                                 return;
1222                         }
1223                 }
1224                 /* Consume printed characters from the buffer. */
1225                 buffer_consume(&stderr_buffer, len);
1226                 stderr_bytes += len;
1227         }
1228 }
1229
1230 /*
1231  * Get packets from the connection input buffer, and process them as long as
1232  * there are packets available.
1233  *
1234  * Any unknown packets received during the actual
1235  * session cause the session to terminate.  This is
1236  * intended to make debugging easier since no
1237  * confirmations are sent.  Any compatible protocol
1238  * extensions must be negotiated during the
1239  * preparatory phase.
1240  */
1241
1242 static void
1243 client_process_buffered_input_packets(void)
1244 {
1245         dispatch_run(DISPATCH_NONBLOCK, &quit_pending,
1246             compat20 ? xxx_kex : NULL);
1247 }
1248
1249 /* scan buf[] for '~' before sending data to the peer */
1250
1251 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */
1252 void *
1253 client_new_escape_filter_ctx(int escape_char)
1254 {
1255         struct escape_filter_ctx *ret;
1256
1257         ret = xmalloc(sizeof(*ret));
1258         ret->escape_pending = 0;
1259         ret->escape_char = escape_char;
1260         return (void *)ret;
1261 }
1262
1263 /* Free the escape filter context on channel free */
1264 void
1265 client_filter_cleanup(int cid, void *ctx)
1266 {
1267         xfree(ctx);
1268 }
1269
1270 int
1271 client_simple_escape_filter(Channel *c, char *buf, int len)
1272 {
1273         if (c->extended_usage != CHAN_EXTENDED_WRITE)
1274                 return 0;
1275
1276         return process_escapes(c, &c->input, &c->output, &c->extended,
1277             buf, len);
1278 }
1279
1280 static void
1281 client_channel_closed(int id, void *arg)
1282 {
1283         channel_cancel_cleanup(id);
1284         session_closed = 1;
1285         leave_raw_mode();
1286 }
1287
1288 /*
1289  * Implements the interactive session with the server.  This is called after
1290  * the user has been authenticated, and a command has been started on the
1291  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1292  * used as an escape character for terminating or suspending the session.
1293  */
1294
1295 int
1296 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1297 {
1298         fd_set *readset = NULL, *writeset = NULL;
1299         double start_time, total_time;
1300         int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
1301         u_int nalloc = 0;
1302         char buf[100];
1303
1304         debug("Entering interactive session.");
1305
1306         start_time = get_current_time();
1307
1308         /* Initialize variables. */
1309         escape_pending1 = 0;
1310         last_was_cr = 1;
1311         exit_status = -1;
1312         stdin_eof = 0;
1313         buffer_high = 64 * 1024;
1314         connection_in = packet_get_connection_in();
1315         connection_out = packet_get_connection_out();
1316         max_fd = MAX(connection_in, connection_out);
1317         if (muxserver_sock != -1)
1318                 max_fd = MAX(max_fd, muxserver_sock);
1319
1320         if (!compat20) {
1321                 /* enable nonblocking unless tty */
1322                 if (!isatty(fileno(stdin)))
1323                         set_nonblock(fileno(stdin));
1324                 if (!isatty(fileno(stdout)))
1325                         set_nonblock(fileno(stdout));
1326                 if (!isatty(fileno(stderr)))
1327                         set_nonblock(fileno(stderr));
1328                 max_fd = MAX(max_fd, fileno(stdin));
1329                 max_fd = MAX(max_fd, fileno(stdout));
1330                 max_fd = MAX(max_fd, fileno(stderr));
1331         }
1332         stdin_bytes = 0;
1333         stdout_bytes = 0;
1334         stderr_bytes = 0;
1335         quit_pending = 0;
1336         escape_char1 = escape_char_arg;
1337
1338         /* Initialize buffers. */
1339         buffer_init(&stdin_buffer);
1340         buffer_init(&stdout_buffer);
1341         buffer_init(&stderr_buffer);
1342
1343         client_init_dispatch();
1344
1345         /*
1346          * Set signal handlers, (e.g. to restore non-blocking mode)
1347          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1348          */
1349         if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1350                 signal(SIGHUP, signal_handler);
1351         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1352                 signal(SIGINT, signal_handler);
1353         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1354                 signal(SIGQUIT, signal_handler);
1355         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1356                 signal(SIGTERM, signal_handler);
1357         signal(SIGWINCH, window_change_handler);
1358
1359         if (have_pty)
1360                 enter_raw_mode();
1361
1362         if (compat20) {
1363                 session_ident = ssh2_chan_id;
1364                 if (escape_char_arg != SSH_ESCAPECHAR_NONE)
1365                         channel_register_filter(session_ident,
1366                             client_simple_escape_filter, NULL,
1367                             client_filter_cleanup,
1368                             client_new_escape_filter_ctx(escape_char_arg));
1369                 if (session_ident != -1)
1370                         channel_register_cleanup(session_ident,
1371                             client_channel_closed, 0);
1372         } else {
1373                 /* Check if we should immediately send eof on stdin. */
1374                 client_check_initial_eof_on_stdin();
1375         }
1376
1377         /* Main loop of the client for the interactive session mode. */
1378         while (!quit_pending) {
1379
1380                 /* Process buffered packets sent by the server. */
1381                 client_process_buffered_input_packets();
1382
1383                 if (compat20 && session_closed && !channel_still_open())
1384                         break;
1385
1386                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
1387
1388                 if (rekeying) {
1389                         debug("rekeying in progress");
1390                 } else {
1391                         /*
1392                          * Make packets of buffered stdin data, and buffer
1393                          * them for sending to the server.
1394                          */
1395                         if (!compat20)
1396                                 client_make_packets_from_stdin_data();
1397
1398                         /*
1399                          * Make packets from buffered channel data, and
1400                          * enqueue them for sending to the server.
1401                          */
1402                         if (packet_not_very_much_data_to_write())
1403                                 channel_output_poll();
1404
1405                         /*
1406                          * Check if the window size has changed, and buffer a
1407                          * message about it to the server if so.
1408                          */
1409                         client_check_window_change();
1410
1411                         if (quit_pending)
1412                                 break;
1413                 }
1414                 /*
1415                  * Wait until we have something to do (something becomes
1416                  * available on one of the descriptors).
1417                  */
1418                 max_fd2 = max_fd;
1419                 client_wait_until_can_do_something(&readset, &writeset,
1420                     &max_fd2, &nalloc, rekeying);
1421
1422                 if (quit_pending)
1423                         break;
1424
1425                 /* Do channel operations unless rekeying in progress. */
1426                 if (!rekeying) {
1427                         channel_after_select(readset, writeset);
1428                         if (need_rekeying || packet_need_rekeying()) {
1429                                 debug("need rekeying");
1430                                 xxx_kex->done = 0;
1431                                 kex_send_kexinit(xxx_kex);
1432                                 need_rekeying = 0;
1433                         }
1434                 }
1435
1436                 /* Buffer input from the connection.  */
1437                 client_process_net_input(readset);
1438
1439                 /* Accept control connections.  */
1440                 if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) {
1441                         if (muxserver_accept_control())
1442                                 quit_pending = 1;
1443                 }
1444
1445                 if (quit_pending)
1446                         break;
1447
1448                 if (!compat20) {
1449                         /* Buffer data from stdin */
1450                         client_process_input(readset);
1451                         /*
1452                          * Process output to stdout and stderr.  Output to
1453                          * the connection is processed elsewhere (above).
1454                          */
1455                         client_process_output(writeset);
1456                 }
1457
1458                 /*
1459                  * Send as much buffered packet data as possible to the
1460                  * sender.
1461                  */
1462                 if (FD_ISSET(connection_out, writeset))
1463                         packet_write_poll();
1464         }
1465         if (readset)
1466                 xfree(readset);
1467         if (writeset)
1468                 xfree(writeset);
1469
1470         /* Terminate the session. */
1471
1472         /* Stop watching for window change. */
1473         signal(SIGWINCH, SIG_DFL);
1474
1475         channel_free_all();
1476
1477         if (have_pty)
1478                 leave_raw_mode();
1479
1480         /* restore blocking io */
1481         if (!isatty(fileno(stdin)))
1482                 unset_nonblock(fileno(stdin));
1483         if (!isatty(fileno(stdout)))
1484                 unset_nonblock(fileno(stdout));
1485         if (!isatty(fileno(stderr)))
1486                 unset_nonblock(fileno(stderr));
1487
1488         /*
1489          * If there was no shell or command requested, there will be no remote
1490          * exit status to be returned.  In that case, clear error code if the
1491          * connection was deliberately terminated at this end.
1492          */
1493         if (no_shell_flag && received_signal == SIGTERM) {
1494                 received_signal = 0;
1495                 exit_status = 0;
1496         }
1497
1498         if (received_signal)
1499                 fatal("Killed by signal %d.", (int) received_signal);
1500
1501         /*
1502          * In interactive mode (with pseudo tty) display a message indicating
1503          * that the connection has been closed.
1504          */
1505         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1506                 snprintf(buf, sizeof buf,
1507                     "Connection to %.64s closed.\r\n", host);
1508                 buffer_append(&stderr_buffer, buf, strlen(buf));
1509         }
1510
1511         /* Output any buffered data for stdout. */
1512         while (buffer_len(&stdout_buffer) > 0) {
1513                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1514                     buffer_len(&stdout_buffer));
1515                 if (len <= 0) {
1516                         error("Write failed flushing stdout buffer.");
1517                         break;
1518                 }
1519                 buffer_consume(&stdout_buffer, len);
1520                 stdout_bytes += len;
1521         }
1522
1523         /* Output any buffered data for stderr. */
1524         while (buffer_len(&stderr_buffer) > 0) {
1525                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1526                     buffer_len(&stderr_buffer));
1527                 if (len <= 0) {
1528                         error("Write failed flushing stderr buffer.");
1529                         break;
1530                 }
1531                 buffer_consume(&stderr_buffer, len);
1532                 stderr_bytes += len;
1533         }
1534
1535         /* Clear and free any buffers. */
1536         memset(buf, 0, sizeof(buf));
1537         buffer_free(&stdin_buffer);
1538         buffer_free(&stdout_buffer);
1539         buffer_free(&stderr_buffer);
1540
1541         /* Report bytes transferred, and transfer rates. */
1542         total_time = get_current_time() - start_time;
1543         debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f "
1544             "seconds", stdin_bytes, stdout_bytes, stderr_bytes, total_time);
1545         if (total_time > 0)
1546                 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1547                     stdin_bytes / total_time, stdout_bytes / total_time,
1548                     stderr_bytes / total_time);
1549
1550         /* Return the exit status of the program. */
1551         debug("Exit status %d", exit_status);
1552         return exit_status;
1553 }
1554
1555 /*********/
1556
1557 static void
1558 client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
1559 {
1560         u_int data_len;
1561         char *data = packet_get_string(&data_len);
1562         packet_check_eom();
1563         buffer_append(&stdout_buffer, data, data_len);
1564         memset(data, 0, data_len);
1565         xfree(data);
1566 }
1567 static void
1568 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1569 {
1570         u_int data_len;
1571         char *data = packet_get_string(&data_len);
1572         packet_check_eom();
1573         buffer_append(&stderr_buffer, data, data_len);
1574         memset(data, 0, data_len);
1575         xfree(data);
1576 }
1577 static void
1578 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1579 {
1580         exit_status = packet_get_int();
1581         packet_check_eom();
1582         /* Acknowledge the exit. */
1583         packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1584         packet_send();
1585         /*
1586          * Must wait for packet to be sent since we are
1587          * exiting the loop.
1588          */
1589         packet_write_wait();
1590         /* Flag that we want to exit. */
1591         quit_pending = 1;
1592 }
1593 static void
1594 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1595 {
1596         Channel *c = NULL;
1597         int remote_id, sock;
1598
1599         /* Read the remote channel number from the message. */
1600         remote_id = packet_get_int();
1601         packet_check_eom();
1602
1603         /*
1604          * Get a connection to the local authentication agent (this may again
1605          * get forwarded).
1606          */
1607         sock = ssh_get_authentication_socket();
1608
1609         /*
1610          * If we could not connect the agent, send an error message back to
1611          * the server. This should never happen unless the agent dies,
1612          * because authentication forwarding is only enabled if we have an
1613          * agent.
1614          */
1615         if (sock >= 0) {
1616                 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1617                     -1, 0, 0, 0, "authentication agent connection", 1);
1618                 c->remote_id = remote_id;
1619                 c->force_drain = 1;
1620         }
1621         if (c == NULL) {
1622                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1623                 packet_put_int(remote_id);
1624         } else {
1625                 /* Send a confirmation to the remote host. */
1626                 debug("Forwarding authentication connection.");
1627                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1628                 packet_put_int(remote_id);
1629                 packet_put_int(c->self);
1630         }
1631         packet_send();
1632 }
1633
1634 static Channel *
1635 client_request_forwarded_tcpip(const char *request_type, int rchan)
1636 {
1637         Channel *c = NULL;
1638         char *listen_address, *originator_address;
1639         int listen_port, originator_port;
1640
1641         /* Get rest of the packet */
1642         listen_address = packet_get_string(NULL);
1643         listen_port = packet_get_int();
1644         originator_address = packet_get_string(NULL);
1645         originator_port = packet_get_int();
1646         packet_check_eom();
1647
1648         debug("client_request_forwarded_tcpip: listen %s port %d, "
1649             "originator %s port %d", listen_address, listen_port,
1650             originator_address, originator_port);
1651
1652         c = channel_connect_by_listen_address(listen_port,
1653             "forwarded-tcpip", originator_address);
1654
1655         xfree(originator_address);
1656         xfree(listen_address);
1657         return c;
1658 }
1659
1660 static Channel *
1661 client_request_x11(const char *request_type, int rchan)
1662 {
1663         Channel *c = NULL;
1664         char *originator;
1665         int originator_port;
1666         int sock;
1667
1668         if (!options.forward_x11) {
1669                 error("Warning: ssh server tried X11 forwarding.");
1670                 error("Warning: this is probably a break-in attempt by a "
1671                     "malicious server.");
1672                 return NULL;
1673         }
1674         originator = packet_get_string(NULL);
1675         if (datafellows & SSH_BUG_X11FWD) {
1676                 debug2("buggy server: x11 request w/o originator_port");
1677                 originator_port = 0;
1678         } else {
1679                 originator_port = packet_get_int();
1680         }
1681         packet_check_eom();
1682         /* XXX check permission */
1683         debug("client_request_x11: request from %s %d", originator,
1684             originator_port);
1685         xfree(originator);
1686         sock = x11_connect_display();
1687         if (sock < 0)
1688                 return NULL;
1689         c = channel_new("x11",
1690             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1691             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1692         c->force_drain = 1;
1693         return c;
1694 }
1695
1696 static Channel *
1697 client_request_agent(const char *request_type, int rchan)
1698 {
1699         Channel *c = NULL;
1700         int sock;
1701
1702         if (!options.forward_agent) {
1703                 error("Warning: ssh server tried agent forwarding.");
1704                 error("Warning: this is probably a break-in attempt by a "
1705                     "malicious server.");
1706                 return NULL;
1707         }
1708         sock = ssh_get_authentication_socket();
1709         if (sock < 0)
1710                 return NULL;
1711         c = channel_new("authentication agent connection",
1712             SSH_CHANNEL_OPEN, sock, sock, -1,
1713             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1714             "authentication agent connection", 1);
1715         c->force_drain = 1;
1716         return c;
1717 }
1718
1719 int
1720 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun)
1721 {
1722         Channel *c;
1723         int fd;
1724
1725         if (tun_mode == SSH_TUNMODE_NO)
1726                 return 0;
1727
1728         if (!compat20) {
1729                 error("Tunnel forwarding is not support for protocol 1");
1730                 return -1;
1731         }
1732
1733         debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
1734
1735         /* Open local tunnel device */
1736         if ((fd = tun_open(local_tun, tun_mode)) == -1) {
1737                 error("Tunnel device open failed.");
1738                 return -1;
1739         }
1740
1741         c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1742             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1743         c->datagram = 1;
1744
1745 #if defined(SSH_TUN_FILTER)
1746         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1747                 channel_register_filter(c->self, sys_tun_infilter,
1748                     sys_tun_outfilter, NULL, NULL);
1749 #endif
1750
1751         packet_start(SSH2_MSG_CHANNEL_OPEN);
1752         packet_put_cstring("tun@openssh.com");
1753         packet_put_int(c->self);
1754         packet_put_int(c->local_window_max);
1755         packet_put_int(c->local_maxpacket);
1756         packet_put_int(tun_mode);
1757         packet_put_int(remote_tun);
1758         packet_send();
1759
1760         return 0;
1761 }
1762
1763 /* XXXX move to generic input handler */
1764 static void
1765 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
1766 {
1767         Channel *c = NULL;
1768         char *ctype;
1769         int rchan;
1770         u_int rmaxpack, rwindow, len;
1771
1772         ctype = packet_get_string(&len);
1773         rchan = packet_get_int();
1774         rwindow = packet_get_int();
1775         rmaxpack = packet_get_int();
1776
1777         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1778             ctype, rchan, rwindow, rmaxpack);
1779
1780         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1781                 c = client_request_forwarded_tcpip(ctype, rchan);
1782         } else if (strcmp(ctype, "x11") == 0) {
1783                 c = client_request_x11(ctype, rchan);
1784         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1785                 c = client_request_agent(ctype, rchan);
1786         }
1787 /* XXX duplicate : */
1788         if (c != NULL) {
1789                 debug("confirm %s", ctype);
1790                 c->remote_id = rchan;
1791                 c->remote_window = rwindow;
1792                 c->remote_maxpacket = rmaxpack;
1793                 if (c->type != SSH_CHANNEL_CONNECTING) {
1794                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1795                         packet_put_int(c->remote_id);
1796                         packet_put_int(c->self);
1797                         packet_put_int(c->local_window);
1798                         packet_put_int(c->local_maxpacket);
1799                         packet_send();
1800                 }
1801         } else {
1802                 debug("failure %s", ctype);
1803                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1804                 packet_put_int(rchan);
1805                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1806                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1807                         packet_put_cstring("open failed");
1808                         packet_put_cstring("");
1809                 }
1810                 packet_send();
1811         }
1812         xfree(ctype);
1813 }
1814 static void
1815 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
1816 {
1817         Channel *c = NULL;
1818         int exitval, id, reply, success = 0;
1819         char *rtype;
1820
1821         id = packet_get_int();
1822         rtype = packet_get_string(NULL);
1823         reply = packet_get_char();
1824
1825         debug("client_input_channel_req: channel %d rtype %s reply %d",
1826             id, rtype, reply);
1827
1828         if (id == -1) {
1829                 error("client_input_channel_req: request for channel -1");
1830         } else if ((c = channel_lookup(id)) == NULL) {
1831                 error("client_input_channel_req: channel %d: "
1832                     "unknown channel", id);
1833         } else if (strcmp(rtype, "eow@openssh.com") == 0) {
1834                 packet_check_eom();
1835                 chan_rcvd_eow(c);
1836         } else if (strcmp(rtype, "exit-status") == 0) {
1837                 exitval = packet_get_int();
1838                 if (id == session_ident) {
1839                         success = 1;
1840                         exit_status = exitval;
1841                 } else if (c->ctl_fd == -1) {
1842                         error("client_input_channel_req: unexpected channel %d",
1843                             session_ident);
1844                 } else {
1845                         atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
1846                         success = 1;
1847                 }
1848                 packet_check_eom();
1849         }
1850         if (reply) {
1851                 packet_start(success ?
1852                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1853                 packet_put_int(id);
1854                 packet_send();
1855         }
1856         xfree(rtype);
1857 }
1858 static void
1859 client_input_global_request(int type, u_int32_t seq, void *ctxt)
1860 {
1861         char *rtype;
1862         int want_reply;
1863         int success = 0;
1864
1865         rtype = packet_get_string(NULL);
1866         want_reply = packet_get_char();
1867         debug("client_input_global_request: rtype %s want_reply %d",
1868             rtype, want_reply);
1869         if (want_reply) {
1870                 packet_start(success ?
1871                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1872                 packet_send();
1873                 packet_write_wait();
1874         }
1875         xfree(rtype);
1876 }
1877
1878 void
1879 client_session2_setup(int id, int want_tty, int want_subsystem,
1880     const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env)
1881 {
1882         int len;
1883         Channel *c = NULL;
1884
1885         debug2("%s: id %d", __func__, id);
1886
1887         if ((c = channel_lookup(id)) == NULL)
1888                 fatal("client_session2_setup: channel %d: unknown channel", id);
1889
1890         if (want_tty) {
1891                 struct winsize ws;
1892
1893                 /* Store window size in the packet. */
1894                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
1895                         memset(&ws, 0, sizeof(ws));
1896
1897                 channel_request_start(id, "pty-req", 1);
1898                 client_expect_confirm(id, "PTY allocation", 0);
1899                 packet_put_cstring(term != NULL ? term : "");
1900                 packet_put_int((u_int)ws.ws_col);
1901                 packet_put_int((u_int)ws.ws_row);
1902                 packet_put_int((u_int)ws.ws_xpixel);
1903                 packet_put_int((u_int)ws.ws_ypixel);
1904                 if (tiop == NULL)
1905                         tiop = get_saved_tio();
1906                 tty_make_modes(-1, tiop);
1907                 packet_send();
1908                 /* XXX wait for reply */
1909                 c->client_tty = 1;
1910         }
1911
1912         /* Transfer any environment variables from client to server */
1913         if (options.num_send_env != 0 && env != NULL) {
1914                 int i, j, matched;
1915                 char *name, *val;
1916
1917                 debug("Sending environment.");
1918                 for (i = 0; env[i] != NULL; i++) {
1919                         /* Split */
1920                         name = xstrdup(env[i]);
1921                         if ((val = strchr(name, '=')) == NULL) {
1922                                 xfree(name);
1923                                 continue;
1924                         }
1925                         *val++ = '\0';
1926
1927                         matched = 0;
1928                         for (j = 0; j < options.num_send_env; j++) {
1929                                 if (match_pattern(name, options.send_env[j])) {
1930                                         matched = 1;
1931                                         break;
1932                                 }
1933                         }
1934                         if (!matched) {
1935                                 debug3("Ignored env %s", name);
1936                                 xfree(name);
1937                                 continue;
1938                         }
1939
1940                         debug("Sending env %s = %s", name, val);
1941                         channel_request_start(id, "env", 0);
1942                         packet_put_cstring(name);
1943                         packet_put_cstring(val);
1944                         packet_send();
1945                         xfree(name);
1946                 }
1947         }
1948
1949         len = buffer_len(cmd);
1950         if (len > 0) {
1951                 if (len > 900)
1952                         len = 900;
1953                 if (want_subsystem) {
1954                         debug("Sending subsystem: %.*s",
1955                             len, (u_char*)buffer_ptr(cmd));
1956                         channel_request_start(id, "subsystem", 1);
1957                         client_expect_confirm(id, "subsystem", 1);
1958                 } else {
1959                         debug("Sending command: %.*s",
1960                             len, (u_char*)buffer_ptr(cmd));
1961                         channel_request_start(id, "exec", 1);
1962                         client_expect_confirm(id, "exec", 1);
1963                 }
1964                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
1965                 packet_send();
1966         } else {
1967                 channel_request_start(id, "shell", 1);
1968                 client_expect_confirm(id, "shell", 1);
1969                 packet_send();
1970         }
1971 }
1972
1973 static void
1974 client_init_dispatch_20(void)
1975 {
1976         dispatch_init(&dispatch_protocol_error);
1977
1978         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1979         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1980         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1981         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1982         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1983         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1984         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1985         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
1986         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1987         dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
1988         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
1989         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
1990
1991         /* rekeying */
1992         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1993
1994         /* global request reply messages */
1995         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
1996         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
1997 }
1998
1999 static void
2000 client_init_dispatch_13(void)
2001 {
2002         dispatch_init(NULL);
2003         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
2004         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
2005         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
2006         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
2007         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
2008         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
2009         dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
2010         dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
2011         dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
2012
2013         dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
2014             &client_input_agent_open : &deny_input_open);
2015         dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
2016             &x11_input_open : &deny_input_open);
2017 }
2018
2019 static void
2020 client_init_dispatch_15(void)
2021 {
2022         client_init_dispatch_13();
2023         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
2024         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
2025 }
2026
2027 static void
2028 client_init_dispatch(void)
2029 {
2030         if (compat20)
2031                 client_init_dispatch_20();
2032         else if (compat13)
2033                 client_init_dispatch_13();
2034         else
2035                 client_init_dispatch_15();
2036 }
2037
2038 /* client specific fatal cleanup */
2039 void
2040 cleanup_exit(int i)
2041 {
2042         leave_raw_mode();
2043         leave_non_blocking();
2044         if (options.control_path != NULL && muxserver_sock != -1)
2045                 unlink(options.control_path);
2046         _exit(i);
2047 }
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