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1/*
2 *
3 * channels.c
4 *
5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
6 *
7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8 * All rights reserved
9 *
10 * Created: Fri Mar 24 16:35:24 1995 ylo
11 *
12 * This file contains functions for generic socket connection forwarding.
13 * There is also code for initiating connection forwarding for X11 connections,
14 * arbitrary tcp/ip connections, and the authentication agent connection.
15 *
16 * SSH2 support added by Markus Friedl.
17 */
18
19#include "includes.h"
20RCSID("$OpenBSD: channels.c,v 1.63 2000/06/25 20:17:57 provos Exp $");
21
22#include "ssh.h"
23#include "packet.h"
24#include "xmalloc.h"
25#include "buffer.h"
26#include "authfd.h"
27#include "uidswap.h"
28#include "readconf.h"
29#include "servconf.h"
30
31#include "channels.h"
32#include "nchan.h"
33#include "compat.h"
34
35#include "ssh2.h"
36
37/* Maximum number of fake X11 displays to try. */
38#define MAX_DISPLAYS 1000
39
40/* Max len of agent socket */
41#define MAX_SOCKET_NAME 100
42
43/* default window/packet sizes for tcp/x11-fwd-channel */
44#define CHAN_TCP_WINDOW_DEFAULT (8*1024)
45#define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2)
46#define CHAN_X11_WINDOW_DEFAULT (4*1024)
47#define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2)
48
49/*
50 * Pointer to an array containing all allocated channels. The array is
51 * dynamically extended as needed.
52 */
53static Channel *channels = NULL;
54
55/*
56 * Size of the channel array. All slots of the array must always be
57 * initialized (at least the type field); unused slots are marked with type
58 * SSH_CHANNEL_FREE.
59 */
60static int channels_alloc = 0;
61
62/*
63 * Maximum file descriptor value used in any of the channels. This is
64 * updated in channel_allocate.
65 */
66static int channel_max_fd_value = 0;
67
68/* Name and directory of socket for authentication agent forwarding. */
69static char *channel_forwarded_auth_socket_name = NULL;
70static char *channel_forwarded_auth_socket_dir = NULL;
71
72/* Saved X11 authentication protocol name. */
73char *x11_saved_proto = NULL;
74
75/* Saved X11 authentication data. This is the real data. */
76char *x11_saved_data = NULL;
77unsigned int x11_saved_data_len = 0;
78
79/*
80 * Fake X11 authentication data. This is what the server will be sending us;
81 * we should replace any occurrences of this by the real data.
82 */
83char *x11_fake_data = NULL;
84unsigned int x11_fake_data_len;
85
86/*
87 * Data structure for storing which hosts are permitted for forward requests.
88 * The local sides of any remote forwards are stored in this array to prevent
89 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
90 * network (which might be behind a firewall).
91 */
92typedef struct {
93 char *host_to_connect; /* Connect to 'host'. */
94 u_short port_to_connect; /* Connect to 'port'. */
95 u_short listen_port; /* Remote side should listen port number. */
96} ForwardPermission;
97
98/* List of all permitted host/port pairs to connect. */
99static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
100/* Number of permitted host/port pairs in the array. */
101static int num_permitted_opens = 0;
102/*
103 * If this is true, all opens are permitted. This is the case on the server
104 * on which we have to trust the client anyway, and the user could do
105 * anything after logging in anyway.
106 */
107static int all_opens_permitted = 0;
108
109/* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */
110static int have_hostname_in_open = 0;
111
112/* Sets specific protocol options. */
113
114void
115channel_set_options(int hostname_in_open)
116{
117 have_hostname_in_open = hostname_in_open;
118}
119
120/*
121 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
122 * called by the server, because the user could connect to any port anyway,
123 * and the server has no way to know but to trust the client anyway.
124 */
125
126void
127channel_permit_all_opens()
128{
129 all_opens_permitted = 1;
130}
131
132/* lookup channel by id */
133
134Channel *
135channel_lookup(int id)
136{
137 Channel *c;
138 if (id < 0 || id > channels_alloc) {
139 log("channel_lookup: %d: bad id", id);
140 return NULL;
141 }
142 c = &channels[id];
143 if (c->type == SSH_CHANNEL_FREE) {
144 log("channel_lookup: %d: bad id: channel free", id);
145 return NULL;
146 }
147 return c;
148}
149
150/*
151 * Register filedescriptors for a channel, used when allocating a channel or
152 * when the channel consumer/producer is ready, e.g. shell exec'd
153 */
154
155void
156channel_register_fds(Channel *c, int rfd, int wfd, int efd, int extusage)
157{
158 /* Update the maximum file descriptor value. */
159 if (rfd > channel_max_fd_value)
160 channel_max_fd_value = rfd;
161 if (wfd > channel_max_fd_value)
162 channel_max_fd_value = wfd;
163 if (efd > channel_max_fd_value)
164 channel_max_fd_value = efd;
165 /* XXX set close-on-exec -markus */
166
167 c->rfd = rfd;
168 c->wfd = wfd;
169 c->sock = (rfd == wfd) ? rfd : -1;
170 c->efd = efd;
171 c->extended_usage = extusage;
172 if (rfd != -1)
173 set_nonblock(rfd);
174 if (wfd != -1)
175 set_nonblock(wfd);
176 if (efd != -1)
177 set_nonblock(efd);
178}
179
180/*
181 * Allocate a new channel object and set its type and socket. This will cause
182 * remote_name to be freed.
183 */
184
185int
186channel_new(char *ctype, int type, int rfd, int wfd, int efd,
187 int window, int maxpack, int extusage, char *remote_name)
188{
189 int i, found;
190 Channel *c;
191
192 /* Do initial allocation if this is the first call. */
193 if (channels_alloc == 0) {
194 chan_init();
195 channels_alloc = 10;
196 channels = xmalloc(channels_alloc * sizeof(Channel));
197 for (i = 0; i < channels_alloc; i++)
198 channels[i].type = SSH_CHANNEL_FREE;
199 /*
200 * Kludge: arrange a call to channel_stop_listening if we
201 * terminate with fatal().
202 */
203 fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
204 }
205 /* Try to find a free slot where to put the new channel. */
206 for (found = -1, i = 0; i < channels_alloc; i++)
207 if (channels[i].type == SSH_CHANNEL_FREE) {
208 /* Found a free slot. */
209 found = i;
210 break;
211 }
212 if (found == -1) {
213 /* There are no free slots. Take last+1 slot and expand the array. */
214 found = channels_alloc;
215 channels_alloc += 10;
216 debug("channel: expanding %d", channels_alloc);
217 channels = xrealloc(channels, channels_alloc * sizeof(Channel));
218 for (i = found; i < channels_alloc; i++)
219 channels[i].type = SSH_CHANNEL_FREE;
220 }
221 /* Initialize and return new channel number. */
222 c = &channels[found];
223 buffer_init(&c->input);
224 buffer_init(&c->output);
225 buffer_init(&c->extended);
226 chan_init_iostates(c);
227 channel_register_fds(c, rfd, wfd, efd, extusage);
228 c->self = found;
229 c->type = type;
230 c->ctype = ctype;
231 c->local_window = window;
232 c->local_window_max = window;
233 c->local_consumed = 0;
234 c->local_maxpacket = maxpack;
235 c->remote_id = -1;
236 c->remote_name = remote_name;
237 c->remote_window = 0;
238 c->remote_maxpacket = 0;
239 c->cb_fn = NULL;
240 c->cb_arg = NULL;
241 c->cb_event = 0;
242 c->dettach_user = NULL;
243 debug("channel %d: new [%s]", found, remote_name);
244 return found;
245}
246/* old interface XXX */
247int
248channel_allocate(int type, int sock, char *remote_name)
249{
250 return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name);
251}
252
253
254/* Close all channel fd/socket. */
255
256void
257channel_close_fds(Channel *c)
258{
259 if (c->sock != -1) {
260 close(c->sock);
261 c->sock = -1;
262 }
263 if (c->rfd != -1) {
264 close(c->rfd);
265 c->rfd = -1;
266 }
267 if (c->wfd != -1) {
268 close(c->wfd);
269 c->wfd = -1;
270 }
271 if (c->efd != -1) {
272 close(c->efd);
273 c->efd = -1;
274 }
275}
276
277/* Free the channel and close its fd/socket. */
278
279void
280channel_free(int id)
281{
282 Channel *c = channel_lookup(id);
283 if (c == NULL)
284 packet_disconnect("channel free: bad local channel %d", id);
285 debug("channel_free: channel %d: status: %s", id, channel_open_message());
286 if (c->dettach_user != NULL) {
287 debug("channel_free: channel %d: dettaching channel user", id);
288 c->dettach_user(c->self, NULL);
289 }
290 if (c->sock != -1)
291 shutdown(c->sock, SHUT_RDWR);
292 channel_close_fds(c);
293 buffer_free(&c->input);
294 buffer_free(&c->output);
295 buffer_free(&c->extended);
296 c->type = SSH_CHANNEL_FREE;
297 if (c->remote_name) {
298 xfree(c->remote_name);
299 c->remote_name = NULL;
300 }
301}
302
303/*
304 * 'channel_pre*' are called just before select() to add any bits relevant to
305 * channels in the select bitmasks.
306 */
307/*
308 * 'channel_post*': perform any appropriate operations for channels which
309 * have events pending.
310 */
311typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
312chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
313chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
314
315void
316channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
317{
318 FD_SET(c->sock, readset);
319}
320
321void
322channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
323{
324 if (buffer_len(&c->input) < packet_get_maxsize())
325 FD_SET(c->sock, readset);
326 if (buffer_len(&c->output) > 0)
327 FD_SET(c->sock, writeset);
328}
329
330void
331channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
332{
333 /* test whether sockets are 'alive' for read/write */
334 if (c->istate == CHAN_INPUT_OPEN)
335 if (buffer_len(&c->input) < packet_get_maxsize())
336 FD_SET(c->sock, readset);
337 if (c->ostate == CHAN_OUTPUT_OPEN ||
338 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
339 if (buffer_len(&c->output) > 0) {
340 FD_SET(c->sock, writeset);
341 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
342 chan_obuf_empty(c);
343 }
344 }
345}
346
347void
348channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
349{
350 if (c->istate == CHAN_INPUT_OPEN &&
351 c->remote_window > 0 &&
352 buffer_len(&c->input) < c->remote_window)
353 FD_SET(c->rfd, readset);
354 if (c->ostate == CHAN_OUTPUT_OPEN ||
355 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
356 if (buffer_len(&c->output) > 0) {
357 FD_SET(c->wfd, writeset);
358 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
359 chan_obuf_empty(c);
360 }
361 }
362 /** XXX check close conditions, too */
363 if (c->efd != -1) {
364 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
365 buffer_len(&c->extended) > 0)
366 FD_SET(c->efd, writeset);
367 else if (c->extended_usage == CHAN_EXTENDED_READ &&
368 buffer_len(&c->extended) < c->remote_window)
369 FD_SET(c->efd, readset);
370 }
371}
372
373void
374channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
375{
376 if (buffer_len(&c->input) == 0) {
377 packet_start(SSH_MSG_CHANNEL_CLOSE);
378 packet_put_int(c->remote_id);
379 packet_send();
380 c->type = SSH_CHANNEL_CLOSED;
381 debug("Closing channel %d after input drain.", c->self);
382 }
383}
384
385void
386channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
387{
388 if (buffer_len(&c->output) == 0)
389 channel_free(c->self);
390 else
391 FD_SET(c->sock, writeset);
392}
393
394/*
395 * This is a special state for X11 authentication spoofing. An opened X11
396 * connection (when authentication spoofing is being done) remains in this
397 * state until the first packet has been completely read. The authentication
398 * data in that packet is then substituted by the real data if it matches the
399 * fake data, and the channel is put into normal mode.
400 * XXX All this happens at the client side.
401 */
402int
403x11_open_helper(Channel *c)
404{
405 unsigned char *ucp;
406 unsigned int proto_len, data_len;
407
408 /* Check if the fixed size part of the packet is in buffer. */
409 if (buffer_len(&c->output) < 12)
410 return 0;
411
412 /* Parse the lengths of variable-length fields. */
413 ucp = (unsigned char *) buffer_ptr(&c->output);
414 if (ucp[0] == 0x42) { /* Byte order MSB first. */
415 proto_len = 256 * ucp[6] + ucp[7];
416 data_len = 256 * ucp[8] + ucp[9];
417 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
418 proto_len = ucp[6] + 256 * ucp[7];
419 data_len = ucp[8] + 256 * ucp[9];
420 } else {
421 debug("Initial X11 packet contains bad byte order byte: 0x%x",
422 ucp[0]);
423 return -1;
424 }
425
426 /* Check if the whole packet is in buffer. */
427 if (buffer_len(&c->output) <
428 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
429 return 0;
430
431 /* Check if authentication protocol matches. */
432 if (proto_len != strlen(x11_saved_proto) ||
433 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
434 debug("X11 connection uses different authentication protocol.");
435 return -1;
436 }
437 /* Check if authentication data matches our fake data. */
438 if (data_len != x11_fake_data_len ||
439 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
440 x11_fake_data, x11_fake_data_len) != 0) {
441 debug("X11 auth data does not match fake data.");
442 return -1;
443 }
444 /* Check fake data length */
445 if (x11_fake_data_len != x11_saved_data_len) {
446 error("X11 fake_data_len %d != saved_data_len %d",
447 x11_fake_data_len, x11_saved_data_len);
448 return -1;
449 }
450 /*
451 * Received authentication protocol and data match
452 * our fake data. Substitute the fake data with real
453 * data.
454 */
455 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
456 x11_saved_data, x11_saved_data_len);
457 return 1;
458}
459
460void
461channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
462{
463 int ret = x11_open_helper(c);
464 if (ret == 1) {
465 /* Start normal processing for the channel. */
466 c->type = SSH_CHANNEL_OPEN;
467 channel_pre_open_13(c, readset, writeset);
468 } else if (ret == -1) {
469 /*
470 * We have received an X11 connection that has bad
471 * authentication information.
472 */
473 log("X11 connection rejected because of wrong authentication.\r\n");
474 buffer_clear(&c->input);
475 buffer_clear(&c->output);
476 close(c->sock);
477 c->sock = -1;
478 c->type = SSH_CHANNEL_CLOSED;
479 packet_start(SSH_MSG_CHANNEL_CLOSE);
480 packet_put_int(c->remote_id);
481 packet_send();
482 }
483}
484
485void
486channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
487{
488 int ret = x11_open_helper(c);
489 if (ret == 1) {
490 c->type = SSH_CHANNEL_OPEN;
491 if (compat20)
492 channel_pre_open_20(c, readset, writeset);
493 else
494 channel_pre_open_15(c, readset, writeset);
495 } else if (ret == -1) {
496 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
497 chan_read_failed(c); /** force close? */
498 chan_write_failed(c);
499 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
500 }
501}
502
503/* This is our fake X11 server socket. */
504void
505channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
506{
507 struct sockaddr addr;
508 int newsock, newch;
509 socklen_t addrlen;
510 char buf[16384], *remote_hostname;
511 int remote_port;
512
513 if (FD_ISSET(c->sock, readset)) {
514 debug("X11 connection requested.");
515 addrlen = sizeof(addr);
516 newsock = accept(c->sock, &addr, &addrlen);
517 if (newsock < 0) {
518 error("accept: %.100s", strerror(errno));
519 return;
520 }
521 remote_hostname = get_remote_hostname(newsock);
522 remote_port = get_peer_port(newsock);
523 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
524 remote_hostname, remote_port);
525
526 newch = channel_new("x11",
527 SSH_CHANNEL_OPENING, newsock, newsock, -1,
528 c->local_window_max, c->local_maxpacket,
529 0, xstrdup(buf));
530 if (compat20) {
531 packet_start(SSH2_MSG_CHANNEL_OPEN);
532 packet_put_cstring("x11");
533 packet_put_int(newch);
534 packet_put_int(c->local_window_max);
535 packet_put_int(c->local_maxpacket);
536 /* originator host and port */
537 packet_put_cstring(remote_hostname);
538 if (datafellows & SSH_BUG_X11FWD) {
539 debug("ssh2 x11 bug compat mode");
540 } else {
541 packet_put_int(remote_port);
542 }
543 packet_send();
544 } else {
545 packet_start(SSH_SMSG_X11_OPEN);
546 packet_put_int(newch);
547 if (have_hostname_in_open)
548 packet_put_string(buf, strlen(buf));
549 packet_send();
550 }
551 xfree(remote_hostname);
552 }
553}
554
555/*
556 * This socket is listening for connections to a forwarded TCP/IP port.
557 */
558void
559channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
560{
561 struct sockaddr addr;
562 int newsock, newch;
563 socklen_t addrlen;
564 char buf[1024], *remote_hostname;
565 int remote_port;
566
567 if (FD_ISSET(c->sock, readset)) {
568 debug("Connection to port %d forwarding "
569 "to %.100s port %d requested.",
570 c->listening_port, c->path, c->host_port);
571 addrlen = sizeof(addr);
572 newsock = accept(c->sock, &addr, &addrlen);
573 if (newsock < 0) {
574 error("accept: %.100s", strerror(errno));
575 return;
576 }
577 remote_hostname = get_remote_hostname(newsock);
578 remote_port = get_peer_port(newsock);
579 snprintf(buf, sizeof buf,
580 "listen port %d for %.100s port %d, "
581 "connect from %.200s port %d",
582 c->listening_port, c->path, c->host_port,
583 remote_hostname, remote_port);
584 newch = channel_new("direct-tcpip",
585 SSH_CHANNEL_OPENING, newsock, newsock, -1,
586 c->local_window_max, c->local_maxpacket,
587 0, xstrdup(buf));
588 if (compat20) {
589 packet_start(SSH2_MSG_CHANNEL_OPEN);
590 packet_put_cstring("direct-tcpip");
591 packet_put_int(newch);
592 packet_put_int(c->local_window_max);
593 packet_put_int(c->local_maxpacket);
594 /* target host and port */
595 packet_put_string(c->path, strlen(c->path));
596 packet_put_int(c->host_port);
597 /* originator host and port */
598 packet_put_cstring(remote_hostname);
599 packet_put_int(remote_port);
600 packet_send();
601 } else {
602 packet_start(SSH_MSG_PORT_OPEN);
603 packet_put_int(newch);
604 packet_put_string(c->path, strlen(c->path));
605 packet_put_int(c->host_port);
606 if (have_hostname_in_open) {
607 packet_put_string(buf, strlen(buf));
608 }
609 packet_send();
610 }
611 xfree(remote_hostname);
612 }
613}
614
615/*
616 * This is the authentication agent socket listening for connections from
617 * clients.
618 */
619void
620channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
621{
622 struct sockaddr addr;
623 int newsock, newch;
624 socklen_t addrlen;
625
626 if (FD_ISSET(c->sock, readset)) {
627 addrlen = sizeof(addr);
628 newsock = accept(c->sock, &addr, &addrlen);
629 if (newsock < 0) {
630 error("accept from auth socket: %.100s", strerror(errno));
631 return;
632 }
633 newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
634 xstrdup("accepted auth socket"));
635 packet_start(SSH_SMSG_AGENT_OPEN);
636 packet_put_int(newch);
637 packet_send();
638 }
639}
640
641int
642channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
643{
644 char buf[16*1024];
645 int len;
646
647 if (c->rfd != -1 &&
648 FD_ISSET(c->rfd, readset)) {
649 len = read(c->rfd, buf, sizeof(buf));
650 if (len < 0 && (errno == EINTR || errno == EAGAIN))
651 return 1;
652 if (len <= 0) {
653 debug("channel %d: read<=0 rfd %d len %d",
654 c->self, c->rfd, len);
655 if (compat13) {
656 buffer_consume(&c->output, buffer_len(&c->output));
657 c->type = SSH_CHANNEL_INPUT_DRAINING;
658 debug("Channel %d status set to input draining.", c->self);
659 } else {
660 chan_read_failed(c);
661 }
662 return -1;
663 }
664 buffer_append(&c->input, buf, len);
665 }
666 return 1;
667}
668int
669channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
670{
671 int len;
672
673 /* Send buffered output data to the socket. */
674 if (c->wfd != -1 &&
675 FD_ISSET(c->wfd, writeset) &&
676 buffer_len(&c->output) > 0) {
677 len = write(c->wfd, buffer_ptr(&c->output),
678 buffer_len(&c->output));
679 if (len < 0 && (errno == EINTR || errno == EAGAIN))
680 return 1;
681 if (len <= 0) {
682 if (compat13) {
683 buffer_consume(&c->output, buffer_len(&c->output));
684 debug("Channel %d status set to input draining.", c->self);
685 c->type = SSH_CHANNEL_INPUT_DRAINING;
686 } else {
687 chan_write_failed(c);
688 }
689 return -1;
690 }
691 buffer_consume(&c->output, len);
692 if (compat20 && len > 0) {
693 c->local_consumed += len;
694 }
695 }
696 return 1;
697}
698int
699channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
700{
701 char buf[16*1024];
702 int len;
703
704/** XXX handle drain efd, too */
705 if (c->efd != -1) {
706 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
707 FD_ISSET(c->efd, writeset) &&
708 buffer_len(&c->extended) > 0) {
709 len = write(c->efd, buffer_ptr(&c->extended),
710 buffer_len(&c->extended));
711 debug("channel %d: written %d to efd %d",
712 c->self, len, c->efd);
713 if (len > 0) {
714 buffer_consume(&c->extended, len);
715 c->local_consumed += len;
716 }
717 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
718 FD_ISSET(c->efd, readset)) {
719 len = read(c->efd, buf, sizeof(buf));
720 debug("channel %d: read %d from efd %d",
721 c->self, len, c->efd);
722 if (len == 0) {
723 debug("channel %d: closing efd %d",
724 c->self, c->efd);
725 close(c->efd);
726 c->efd = -1;
727 } else if (len > 0)
728 buffer_append(&c->extended, buf, len);
729 }
730 }
731 return 1;
732}
733int
734channel_check_window(Channel *c, fd_set * readset, fd_set * writeset)
735{
736 if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
737 c->local_window < c->local_window_max/2 &&
738 c->local_consumed > 0) {
739 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
740 packet_put_int(c->remote_id);
741 packet_put_int(c->local_consumed);
742 packet_send();
743 debug("channel %d: window %d sent adjust %d",
744 c->self, c->local_window,
745 c->local_consumed);
746 c->local_window += c->local_consumed;
747 c->local_consumed = 0;
748 }
749 return 1;
750}
751
752void
753channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
754{
755 channel_handle_rfd(c, readset, writeset);
756 channel_handle_wfd(c, readset, writeset);
757}
758
759void
760channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
761{
762 channel_handle_rfd(c, readset, writeset);
763 channel_handle_wfd(c, readset, writeset);
764 channel_handle_efd(c, readset, writeset);
765 channel_check_window(c, readset, writeset);
766}
767
768void
769channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
770{
771 int len;
772 /* Send buffered output data to the socket. */
773 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
774 len = write(c->sock, buffer_ptr(&c->output),
775 buffer_len(&c->output));
776 if (len <= 0)
777 buffer_consume(&c->output, buffer_len(&c->output));
778 else
779 buffer_consume(&c->output, len);
780 }
781}
782
783void
784channel_handler_init_20(void)
785{
786 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
787 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
788 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
789 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
790
791 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
792 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
793 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
794}
795
796void
797channel_handler_init_13(void)
798{
799 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
800 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
801 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
802 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
803 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
804 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
805 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
806
807 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
808 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
809 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
810 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
811 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
812}
813
814void
815channel_handler_init_15(void)
816{
817 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
818 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
819 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
820 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
821 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
822
823 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
824 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
825 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
826 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
827}
828
829void
830channel_handler_init(void)
831{
832 int i;
833 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
834 channel_pre[i] = NULL;
835 channel_post[i] = NULL;
836 }
837 if (compat20)
838 channel_handler_init_20();
839 else if (compat13)
840 channel_handler_init_13();
841 else
842 channel_handler_init_15();
843}
844
845void
846channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
847{
848 static int did_init = 0;
849 int i;
850 Channel *c;
851
852 if (!did_init) {
853 channel_handler_init();
854 did_init = 1;
855 }
856 for (i = 0; i < channels_alloc; i++) {
857 c = &channels[i];
858 if (c->type == SSH_CHANNEL_FREE)
859 continue;
860 if (ftab[c->type] == NULL)
861 continue;
862 (*ftab[c->type])(c, readset, writeset);
863 chan_delete_if_full_closed(c);
864 }
865}
866
867void
868channel_prepare_select(fd_set * readset, fd_set * writeset)
869{
870 channel_handler(channel_pre, readset, writeset);
871}
872
873void
874channel_after_select(fd_set * readset, fd_set * writeset)
875{
876 channel_handler(channel_post, readset, writeset);
877}
878
879/* If there is data to send to the connection, send some of it now. */
880
881void
882channel_output_poll()
883{
884 int len, i;
885 Channel *c;
886
887 for (i = 0; i < channels_alloc; i++) {
888 c = &channels[i];
889
890 /* We are only interested in channels that can have buffered incoming data. */
891 if (compat13) {
892 if (c->type != SSH_CHANNEL_OPEN &&
893 c->type != SSH_CHANNEL_INPUT_DRAINING)
894 continue;
895 } else {
896 if (c->type != SSH_CHANNEL_OPEN)
897 continue;
898 if (c->istate != CHAN_INPUT_OPEN &&
899 c->istate != CHAN_INPUT_WAIT_DRAIN)
900 continue;
901 }
902 if (compat20 &&
903 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
904 debug("channel: %d: no data after CLOSE", c->self);
905 continue;
906 }
907
908 /* Get the amount of buffered data for this channel. */
909 len = buffer_len(&c->input);
910 if (len > 0) {
911 /* Send some data for the other side over the secure connection. */
912 if (compat20) {
913 if (len > c->remote_window)
914 len = c->remote_window;
915 if (len > c->remote_maxpacket)
916 len = c->remote_maxpacket;
917 } else {
918 if (packet_is_interactive()) {
919 if (len > 1024)
920 len = 512;
921 } else {
922 /* Keep the packets at reasonable size. */
923 if (len > packet_get_maxsize()/2)
924 len = packet_get_maxsize()/2;
925 }
926 }
927 if (len > 0) {
928 packet_start(compat20 ?
929 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
930 packet_put_int(c->remote_id);
931 packet_put_string(buffer_ptr(&c->input), len);
932 packet_send();
933 buffer_consume(&c->input, len);
934 c->remote_window -= len;
935 }
936 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
937 if (compat13)
938 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
939 /*
940 * input-buffer is empty and read-socket shutdown:
941 * tell peer, that we will not send more data: send IEOF
942 */
943 chan_ibuf_empty(c);
944 }
945 /* Send extended data, i.e. stderr */
946 if (compat20 &&
947 c->remote_window > 0 &&
948 (len = buffer_len(&c->extended)) > 0 &&
949 c->extended_usage == CHAN_EXTENDED_READ) {
950 if (len > c->remote_window)
951 len = c->remote_window;
952 if (len > c->remote_maxpacket)
953 len = c->remote_maxpacket;
954 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
955 packet_put_int(c->remote_id);
956 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
957 packet_put_string(buffer_ptr(&c->extended), len);
958 packet_send();
959 buffer_consume(&c->extended, len);
960 c->remote_window -= len;
961 }
962 }
963}
964
965/*
966 * This is called when a packet of type CHANNEL_DATA has just been received.
967 * The message type has already been consumed, but channel number and data is
968 * still there.
969 */
970
971void
972channel_input_data(int type, int plen)
973{
974 int id;
975 char *data;
976 unsigned int data_len;
977 Channel *c;
978
979 /* Get the channel number and verify it. */
980 id = packet_get_int();
981 c = channel_lookup(id);
982 if (c == NULL)
983 packet_disconnect("Received data for nonexistent channel %d.", id);
984
985 /* Ignore any data for non-open channels (might happen on close) */
986 if (c->type != SSH_CHANNEL_OPEN &&
987 c->type != SSH_CHANNEL_X11_OPEN)
988 return;
989
990 /* same for protocol 1.5 if output end is no longer open */
991 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
992 return;
993
994 /* Get the data. */
995 data = packet_get_string(&data_len);
996 packet_done();
997
998 if (compat20){
999 if (data_len > c->local_maxpacket) {
1000 log("channel %d: rcvd big packet %d, maxpack %d",
1001 c->self, data_len, c->local_maxpacket);
1002 }
1003 if (data_len > c->local_window) {
1004 log("channel %d: rcvd too much data %d, win %d",
1005 c->self, data_len, c->local_window);
1006 xfree(data);
1007 return;
1008 }
1009 c->local_window -= data_len;
1010 }else{
1011 packet_integrity_check(plen, 4 + 4 + data_len, type);
1012 }
1013 buffer_append(&c->output, data, data_len);
1014 xfree(data);
1015}
1016void
1017channel_input_extended_data(int type, int plen)
1018{
1019 int id;
1020 int tcode;
1021 char *data;
1022 unsigned int data_len;
1023 Channel *c;
1024
1025 /* Get the channel number and verify it. */
1026 id = packet_get_int();
1027 c = channel_lookup(id);
1028
1029 if (c == NULL)
1030 packet_disconnect("Received extended_data for bad channel %d.", id);
1031 if (c->type != SSH_CHANNEL_OPEN) {
1032 log("channel %d: ext data for non open", id);
1033 return;
1034 }
1035 tcode = packet_get_int();
1036 if (c->efd == -1 ||
1037 c->extended_usage != CHAN_EXTENDED_WRITE ||
1038 tcode != SSH2_EXTENDED_DATA_STDERR) {
1039 log("channel %d: bad ext data", c->self);
1040 return;
1041 }
1042 data = packet_get_string(&data_len);
1043 packet_done();
1044 if (data_len > c->local_window) {
1045 log("channel %d: rcvd too much extended_data %d, win %d",
1046 c->self, data_len, c->local_window);
1047 xfree(data);
1048 return;
1049 }
1050 debug("channel %d: rcvd ext data %d", c->self, data_len);
1051 c->local_window -= data_len;
1052 buffer_append(&c->extended, data, data_len);
1053 xfree(data);
1054}
1055
1056
1057/*
1058 * Returns true if no channel has too much buffered data, and false if one or
1059 * more channel is overfull.
1060 */
1061
1062int
1063channel_not_very_much_buffered_data()
1064{
1065 unsigned int i;
1066 Channel *c;
1067
1068 for (i = 0; i < channels_alloc; i++) {
1069 c = &channels[i];
1070 if (c->type == SSH_CHANNEL_OPEN) {
1071 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
1072 debug("channel %d: big input buffer %d",
1073 c->self, buffer_len(&c->input));
1074 return 0;
1075 }
1076 if (buffer_len(&c->output) > packet_get_maxsize()) {
1077 debug("channel %d: big output buffer %d",
1078 c->self, buffer_len(&c->output));
1079 return 0;
1080 }
1081 }
1082 }
1083 return 1;
1084}
1085
1086void
1087channel_input_ieof(int type, int plen)
1088{
1089 int id;
1090 Channel *c;
1091
1092 packet_integrity_check(plen, 4, type);
1093
1094 id = packet_get_int();
1095 c = channel_lookup(id);
1096 if (c == NULL)
1097 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1098 chan_rcvd_ieof(c);
1099}
1100
1101void
1102channel_input_close(int type, int plen)
1103{
1104 int id;
1105 Channel *c;
1106
1107 packet_integrity_check(plen, 4, type);
1108
1109 id = packet_get_int();
1110 c = channel_lookup(id);
1111 if (c == NULL)
1112 packet_disconnect("Received close for nonexistent channel %d.", id);
1113
1114 /*
1115 * Send a confirmation that we have closed the channel and no more
1116 * data is coming for it.
1117 */
1118 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1119 packet_put_int(c->remote_id);
1120 packet_send();
1121
1122 /*
1123 * If the channel is in closed state, we have sent a close request,
1124 * and the other side will eventually respond with a confirmation.
1125 * Thus, we cannot free the channel here, because then there would be
1126 * no-one to receive the confirmation. The channel gets freed when
1127 * the confirmation arrives.
1128 */
1129 if (c->type != SSH_CHANNEL_CLOSED) {
1130 /*
1131 * Not a closed channel - mark it as draining, which will
1132 * cause it to be freed later.
1133 */
1134 buffer_consume(&c->input, buffer_len(&c->input));
1135 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1136 }
1137}
1138
1139/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1140void
1141channel_input_oclose(int type, int plen)
1142{
1143 int id = packet_get_int();
1144 Channel *c = channel_lookup(id);
1145 packet_integrity_check(plen, 4, type);
1146 if (c == NULL)
1147 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1148 chan_rcvd_oclose(c);
1149}
1150
1151void
1152channel_input_close_confirmation(int type, int plen)
1153{
1154 int id = packet_get_int();
1155 Channel *c = channel_lookup(id);
1156
1157 packet_done();
1158 if (c == NULL)
1159 packet_disconnect("Received close confirmation for "
1160 "out-of-range channel %d.", id);
1161 if (c->type != SSH_CHANNEL_CLOSED)
1162 packet_disconnect("Received close confirmation for "
1163 "non-closed channel %d (type %d).", id, c->type);
1164 channel_free(c->self);
1165}
1166
1167void
1168channel_input_open_confirmation(int type, int plen)
1169{
1170 int id, remote_id;
1171 Channel *c;
1172
1173 if (!compat20)
1174 packet_integrity_check(plen, 4 + 4, type);
1175
1176 id = packet_get_int();
1177 c = channel_lookup(id);
1178
1179 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1180 packet_disconnect("Received open confirmation for "
1181 "non-opening channel %d.", id);
1182 remote_id = packet_get_int();
1183 /* Record the remote channel number and mark that the channel is now open. */
1184 c->remote_id = remote_id;
1185 c->type = SSH_CHANNEL_OPEN;
1186
1187 if (compat20) {
1188 c->remote_window = packet_get_int();
1189 c->remote_maxpacket = packet_get_int();
1190 packet_done();
1191 if (c->cb_fn != NULL && c->cb_event == type) {
1192 debug("callback start");
1193 c->cb_fn(c->self, c->cb_arg);
1194 debug("callback done");
1195 }
1196 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1197 c->remote_window, c->remote_maxpacket);
1198 }
1199}
1200
1201void
1202channel_input_open_failure(int type, int plen)
1203{
1204 int id;
1205 Channel *c;
1206
1207 if (!compat20)
1208 packet_integrity_check(plen, 4, type);
1209
1210 id = packet_get_int();
1211 c = channel_lookup(id);
1212
1213 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1214 packet_disconnect("Received open failure for "
1215 "non-opening channel %d.", id);
1216 if (compat20) {
1217 int reason = packet_get_int();
1218 char *msg = packet_get_string(NULL);
1219 char *lang = packet_get_string(NULL);
1220 log("channel_open_failure: %d: reason %d: %s", id, reason, msg);
1221 packet_done();
1222 xfree(msg);
1223 xfree(lang);
1224 }
1225 /* Free the channel. This will also close the socket. */
1226 channel_free(id);
1227}
1228
1229void
1230channel_input_channel_request(int type, int plen)
1231{
1232 int id;
1233 Channel *c;
1234
1235 id = packet_get_int();
1236 c = channel_lookup(id);
1237
1238 if (c == NULL ||
1239 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1240 packet_disconnect("Received request for "
1241 "non-open channel %d.", id);
1242 if (c->cb_fn != NULL && c->cb_event == type) {
1243 debug("callback start");
1244 c->cb_fn(c->self, c->cb_arg);
1245 debug("callback done");
1246 } else {
1247 char *service = packet_get_string(NULL);
1248 debug("channel: %d rcvd request for %s", c->self, service);
1249debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1250 xfree(service);
1251 }
1252}
1253
1254void
1255channel_input_window_adjust(int type, int plen)
1256{
1257 Channel *c;
1258 int id, adjust;
1259
1260 if (!compat20)
1261 return;
1262
1263 /* Get the channel number and verify it. */
1264 id = packet_get_int();
1265 c = channel_lookup(id);
1266
1267 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1268 log("Received window adjust for "
1269 "non-open channel %d.", id);
1270 return;
1271 }
1272 adjust = packet_get_int();
1273 packet_done();
1274 debug("channel %d: rcvd adjust %d", id, adjust);
1275 c->remote_window += adjust;
1276}
1277
1278/*
1279 * Stops listening for channels, and removes any unix domain sockets that we
1280 * might have.
1281 */
1282
1283void
1284channel_stop_listening()
1285{
1286 int i;
1287 for (i = 0; i < channels_alloc; i++) {
1288 switch (channels[i].type) {
1289 case SSH_CHANNEL_AUTH_SOCKET:
1290 close(channels[i].sock);
1291 remove(channels[i].path);
1292 channel_free(i);
1293 break;
1294 case SSH_CHANNEL_PORT_LISTENER:
1295 case SSH_CHANNEL_X11_LISTENER:
1296 close(channels[i].sock);
1297 channel_free(i);
1298 break;
1299 default:
1300 break;
1301 }
1302 }
1303}
1304
1305/*
1306 * Closes the sockets/fds of all channels. This is used to close extra file
1307 * descriptors after a fork.
1308 */
1309
1310void
1311channel_close_all()
1312{
1313 int i;
1314 for (i = 0; i < channels_alloc; i++)
1315 if (channels[i].type != SSH_CHANNEL_FREE)
1316 channel_close_fds(&channels[i]);
1317}
1318
1319/* Returns the maximum file descriptor number used by the channels. */
1320
1321int
1322channel_max_fd()
1323{
1324 return channel_max_fd_value;
1325}
1326
1327/* Returns true if any channel is still open. */
1328
1329int
1330channel_still_open()
1331{
1332 unsigned int i;
1333 for (i = 0; i < channels_alloc; i++)
1334 switch (channels[i].type) {
1335 case SSH_CHANNEL_FREE:
1336 case SSH_CHANNEL_X11_LISTENER:
1337 case SSH_CHANNEL_PORT_LISTENER:
1338 case SSH_CHANNEL_CLOSED:
1339 case SSH_CHANNEL_AUTH_SOCKET:
1340 continue;
1341 case SSH_CHANNEL_LARVAL:
1342 if (!compat20)
1343 fatal("cannot happen: SSH_CHANNEL_LARVAL");
1344 continue;
1345 case SSH_CHANNEL_OPENING:
1346 case SSH_CHANNEL_OPEN:
1347 case SSH_CHANNEL_X11_OPEN:
1348 return 1;
1349 case SSH_CHANNEL_INPUT_DRAINING:
1350 case SSH_CHANNEL_OUTPUT_DRAINING:
1351 if (!compat13)
1352 fatal("cannot happen: OUT_DRAIN");
1353 return 1;
1354 default:
1355 fatal("channel_still_open: bad channel type %d", channels[i].type);
1356 /* NOTREACHED */
1357 }
1358 return 0;
1359}
1360
1361/*
1362 * Returns a message describing the currently open forwarded connections,
1363 * suitable for sending to the client. The message contains crlf pairs for
1364 * newlines.
1365 */
1366
1367char *
1368channel_open_message()
1369{
1370 Buffer buffer;
1371 int i;
1372 char buf[512], *cp;
1373
1374 buffer_init(&buffer);
1375 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1376 buffer_append(&buffer, buf, strlen(buf));
1377 for (i = 0; i < channels_alloc; i++) {
1378 Channel *c = &channels[i];
1379 switch (c->type) {
1380 case SSH_CHANNEL_FREE:
1381 case SSH_CHANNEL_X11_LISTENER:
1382 case SSH_CHANNEL_PORT_LISTENER:
1383 case SSH_CHANNEL_CLOSED:
1384 case SSH_CHANNEL_AUTH_SOCKET:
1385 continue;
1386 case SSH_CHANNEL_LARVAL:
1387 case SSH_CHANNEL_OPENING:
1388 case SSH_CHANNEL_OPEN:
1389 case SSH_CHANNEL_X11_OPEN:
1390 case SSH_CHANNEL_INPUT_DRAINING:
1391 case SSH_CHANNEL_OUTPUT_DRAINING:
1392 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1393 c->self, c->remote_name,
1394 c->type, c->remote_id,
1395 c->istate, buffer_len(&c->input),
1396 c->ostate, buffer_len(&c->output),
1397 c->rfd, c->wfd);
1398 buffer_append(&buffer, buf, strlen(buf));
1399 continue;
1400 default:
1401 fatal("channel_open_message: bad channel type %d", c->type);
1402 /* NOTREACHED */
1403 }
1404 }
1405 buffer_append(&buffer, "\0", 1);
1406 cp = xstrdup(buffer_ptr(&buffer));
1407 buffer_free(&buffer);
1408 return cp;
1409}
1410
1411/*
1412 * Initiate forwarding of connections to local port "port" through the secure
1413 * channel to host:port from remote side.
1414 */
1415
1416void
1417channel_request_local_forwarding(u_short port, const char *host,
1418 u_short host_port, int gateway_ports)
1419{
1420 int success, ch, sock, on = 1;
1421 struct addrinfo hints, *ai, *aitop;
1422 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1423 struct linger linger;
1424
1425 if (strlen(host) > sizeof(channels[0].path) - 1)
1426 packet_disconnect("Forward host name too long.");
1427
1428 /*
1429 * getaddrinfo returns a loopback address if the hostname is
1430 * set to NULL and hints.ai_flags is not AI_PASSIVE
1431 */
1432 memset(&hints, 0, sizeof(hints));
1433 hints.ai_family = IPv4or6;
1434 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1435 hints.ai_socktype = SOCK_STREAM;
1436 snprintf(strport, sizeof strport, "%d", port);
1437 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1438 packet_disconnect("getaddrinfo: fatal error");
1439
1440 success = 0;
1441 for (ai = aitop; ai; ai = ai->ai_next) {
1442 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1443 continue;
1444 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1445 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1446 error("channel_request_local_forwarding: getnameinfo failed");
1447 continue;
1448 }
1449 /* Create a port to listen for the host. */
1450 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1451 if (sock < 0) {
1452 /* this is no error since kernel may not support ipv6 */
1453 verbose("socket: %.100s", strerror(errno));
1454 continue;
1455 }
1456 /*
1457 * Set socket options. We would like the socket to disappear
1458 * as soon as it has been closed for whatever reason.
1459 */
1460 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1461 linger.l_onoff = 1;
1462 linger.l_linger = 5;
1463 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1464 debug("Local forwarding listening on %s port %s.", ntop, strport);
1465
1466 /* Bind the socket to the address. */
1467 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1468 /* address can be in use ipv6 address is already bound */
1469 if (!ai->ai_next)
1470 error("bind: %.100s", strerror(errno));
1471 else
1472 verbose("bind: %.100s", strerror(errno));
1473
1474 close(sock);
1475 continue;
1476 }
1477 /* Start listening for connections on the socket. */
1478 if (listen(sock, 5) < 0) {
1479 error("listen: %.100s", strerror(errno));
1480 close(sock);
1481 continue;
1482 }
1483 /* Allocate a channel number for the socket. */
1484 ch = channel_new(
1485 "port listener", SSH_CHANNEL_PORT_LISTENER,
1486 sock, sock, -1,
1487 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1488 0, xstrdup("port listener"));
1489 strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
1490 channels[ch].host_port = host_port;
1491 channels[ch].listening_port = port;
1492 success = 1;
1493 }
1494 if (success == 0)
1495 packet_disconnect("cannot listen port: %d", port);
1496 freeaddrinfo(aitop);
1497}
1498
1499/*
1500 * Initiate forwarding of connections to port "port" on remote host through
1501 * the secure channel to host:port from local side.
1502 */
1503
1504void
1505channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect,
1506 u_short port_to_connect)
1507{
1508 int payload_len;
1509 /* Record locally that connection to this host/port is permitted. */
1510 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1511 fatal("channel_request_remote_forwarding: too many forwards");
1512
1513 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
1514 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
1515 permitted_opens[num_permitted_opens].listen_port = listen_port;
1516 num_permitted_opens++;
1517
1518 /* Send the forward request to the remote side. */
1519 if (compat20) {
1520 const char *address_to_bind = "0.0.0.0";
1521 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1522 packet_put_cstring("tcpip-forward");
1523 packet_put_char(0); /* boolean: want reply */
1524 packet_put_cstring(address_to_bind);
1525 packet_put_int(listen_port);
1526 } else {
1527 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
1528 packet_put_int(listen_port);
1529 packet_put_cstring(host_to_connect);
1530 packet_put_int(port_to_connect);
1531 packet_send();
1532 packet_write_wait();
1533 /*
1534 * Wait for response from the remote side. It will send a disconnect
1535 * message on failure, and we will never see it here.
1536 */
1537 packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
1538 }
1539}
1540
1541/*
1542 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1543 * listening for the port, and sends back a success reply (or disconnect
1544 * message if there was an error). This never returns if there was an error.
1545 */
1546
1547void
1548channel_input_port_forward_request(int is_root, int gateway_ports)
1549{
1550 u_short port, host_port;
1551 char *hostname;
1552
1553 /* Get arguments from the packet. */
1554 port = packet_get_int();
1555 hostname = packet_get_string(NULL);
1556 host_port = packet_get_int();
1557
1558 /*
1559 * Check that an unprivileged user is not trying to forward a
1560 * privileged port.
1561 */
1562 if (port < IPPORT_RESERVED && !is_root)
1563 packet_disconnect("Requested forwarding of port %d but user is not root.",
1564 port);
1565 /*
1566 * Initiate forwarding,
1567 */
1568 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
1569
1570 /* Free the argument string. */
1571 xfree(hostname);
1572}
1573
1574/* XXX move to aux.c */
1575int
1576channel_connect_to(const char *host, u_short host_port)
1577{
1578 struct addrinfo hints, *ai, *aitop;
1579 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1580 int gaierr;
1581 int sock = -1;
1582
1583 memset(&hints, 0, sizeof(hints));
1584 hints.ai_family = IPv4or6;
1585 hints.ai_socktype = SOCK_STREAM;
1586 snprintf(strport, sizeof strport, "%d", host_port);
1587 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
1588 error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
1589 return -1;
1590 }
1591 for (ai = aitop; ai; ai = ai->ai_next) {
1592 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1593 continue;
1594 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1595 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1596 error("channel_connect_to: getnameinfo failed");
1597 continue;
1598 }
1599 /* Create the socket. */
1600 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1601 if (sock < 0) {
1602 error("socket: %.100s", strerror(errno));
1603 continue;
1604 }
1605 /* Connect to the host/port. */
1606 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1607 error("connect %.100s port %s: %.100s", ntop, strport,
1608 strerror(errno));
1609 close(sock);
1610 continue; /* fail -- try next */
1611 }
1612 break; /* success */
1613
1614 }
1615 freeaddrinfo(aitop);
1616 if (!ai) {
1617 error("connect %.100s port %d: failed.", host, host_port);
1618 return -1;
1619 }
1620 /* success */
1621 return sock;
1622}
1623
1624/*
1625 * This is called after receiving PORT_OPEN message. This attempts to
1626 * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
1627 * or CHANNEL_OPEN_FAILURE.
1628 */
1629
1630void
1631channel_input_port_open(int type, int plen)
1632{
1633 u_short host_port;
1634 char *host, *originator_string;
1635 int remote_channel, sock = -1, newch, i, denied;
1636 unsigned int host_len, originator_len;
1637
1638 /* Get remote channel number. */
1639 remote_channel = packet_get_int();
1640
1641 /* Get host name to connect to. */
1642 host = packet_get_string(&host_len);
1643
1644 /* Get port to connect to. */
1645 host_port = packet_get_int();
1646
1647 /* Get remote originator name. */
1648 if (have_hostname_in_open) {
1649 originator_string = packet_get_string(&originator_len);
1650 originator_len += 4; /* size of packet_int */
1651 } else {
1652 originator_string = xstrdup("unknown (remote did not supply name)");
1653 originator_len = 0; /* no originator supplied */
1654 }
1655
1656 packet_integrity_check(plen,
1657 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
1658
1659 /* Check if opening that port is permitted. */
1660 denied = 0;
1661 if (!all_opens_permitted) {
1662 /* Go trough all permitted ports. */
1663 for (i = 0; i < num_permitted_opens; i++)
1664 if (permitted_opens[i].port_to_connect == host_port &&
1665 strcmp(permitted_opens[i].host_to_connect, host) == 0)
1666 break;
1667
1668 /* Check if we found the requested port among those permitted. */
1669 if (i >= num_permitted_opens) {
1670 /* The port is not permitted. */
1671 log("Received request to connect to %.100s:%d, but the request was denied.",
1672 host, host_port);
1673 denied = 1;
1674 }
1675 }
1676 sock = denied ? -1 : channel_connect_to(host, host_port);
1677 if (sock > 0) {
1678 /* Allocate a channel for this connection. */
1679 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
1680 channels[newch].remote_id = remote_channel;
1681
1682 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1683 packet_put_int(remote_channel);
1684 packet_put_int(newch);
1685 packet_send();
1686 } else {
1687 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1688 packet_put_int(remote_channel);
1689 packet_send();
1690 }
1691 xfree(host);
1692}
1693
1694/*
1695 * Creates an internet domain socket for listening for X11 connections.
1696 * Returns a suitable value for the DISPLAY variable, or NULL if an error
1697 * occurs.
1698 */
1699
1700#define NUM_SOCKS 10
1701
1702char *
1703x11_create_display_inet(int screen_number, int x11_display_offset)
1704{
1705 int display_number, sock;
1706 u_short port;
1707 struct addrinfo hints, *ai, *aitop;
1708 char strport[NI_MAXSERV];
1709 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
1710 char display[512];
1711 char hostname[MAXHOSTNAMELEN];
1712
1713 for (display_number = x11_display_offset;
1714 display_number < MAX_DISPLAYS;
1715 display_number++) {
1716 port = 6000 + display_number;
1717 memset(&hints, 0, sizeof(hints));
1718 hints.ai_family = IPv4or6;
1719 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
1720 hints.ai_socktype = SOCK_STREAM;
1721 snprintf(strport, sizeof strport, "%d", port);
1722 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
1723 error("getaddrinfo: %.100s", gai_strerror(gaierr));
1724 return NULL;
1725 }
1726 for (ai = aitop; ai; ai = ai->ai_next) {
1727 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1728 continue;
1729 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1730 if (sock < 0) {
1731 if (errno != EINVAL) {
1732 error("socket: %.100s", strerror(errno));
1733 return NULL;
1734 } else {
1735 debug("Socket family %d not supported [X11 disp create]", ai->ai_family);
1736 continue;
1737 }
1738 }
1739 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1740 debug("bind port %d: %.100s", port, strerror(errno));
1741 shutdown(sock, SHUT_RDWR);
1742 close(sock);
1743
1744 if (ai->ai_next)
1745 continue;
1746
1747 for (n = 0; n < num_socks; n++) {
1748 shutdown(socks[n], SHUT_RDWR);
1749 close(socks[n]);
1750 }
1751 num_socks = 0;
1752 break;
1753 }
1754 socks[num_socks++] = sock;
1755#ifndef DONT_TRY_OTHER_AF
1756 if (num_socks == NUM_SOCKS)
1757 break;
1758#else
1759 break;
1760#endif
1761 }
1762 if (num_socks > 0)
1763 break;
1764 }
1765 if (display_number >= MAX_DISPLAYS) {
1766 error("Failed to allocate internet-domain X11 display socket.");
1767 return NULL;
1768 }
1769 /* Start listening for connections on the socket. */
1770 for (n = 0; n < num_socks; n++) {
1771 sock = socks[n];
1772 if (listen(sock, 5) < 0) {
1773 error("listen: %.100s", strerror(errno));
1774 shutdown(sock, SHUT_RDWR);
1775 close(sock);
1776 return NULL;
1777 }
1778 }
1779
1780 /* Set up a suitable value for the DISPLAY variable. */
1781
1782 if (gethostname(hostname, sizeof(hostname)) < 0)
1783 fatal("gethostname: %.100s", strerror(errno));
1784
1785#ifdef IPADDR_IN_DISPLAY
1786 /*
1787 * HPUX detects the local hostname in the DISPLAY variable and tries
1788 * to set up a shared memory connection to the server, which it
1789 * incorrectly supposes to be local.
1790 *
1791 * The workaround - as used in later $$H and other programs - is
1792 * is to set display to the host's IP address.
1793 */
1794 {
1795 struct hostent *he;
1796 struct in_addr my_addr;
1797
1798 he = gethostbyname(hostname);
1799 if (he == NULL) {
1800 error("[X11-broken-fwd-hostname-workaround] Could not get "
1801 "IP address for hostname %s.", hostname);
1802
1803 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
1804 "Could not get IP address for hostname %s.", hostname);
1805
1806 shutdown(sock, SHUT_RDWR);
1807 close(sock);
1808
1809 return NULL;
1810 }
1811
1812 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
1813
1814 /* Set DISPLAY to <ip address>:screen.display */
1815 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
1816 display_number, screen_number);
1817 }
1818#else /* IPADDR_IN_DISPLAY */
1819 /* Just set DISPLAY to hostname:screen.display */
1820 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1821 display_number, screen_number);
1822#endif /* IPADDR_IN_DISPLAY */
1823
1824 /* Allocate a channel for each socket. */
1825 for (n = 0; n < num_socks; n++) {
1826 sock = socks[n];
1827 (void) channel_new("x11 listener",
1828 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
1829 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1830 0, xstrdup("X11 inet listener"));
1831 }
1832
1833 /* Return a suitable value for the DISPLAY environment variable. */
1834 return xstrdup(display);
1835}
1836
1837#ifndef X_UNIX_PATH
1838#define X_UNIX_PATH "/tmp/.X11-unix/X"
1839#endif
1840
1841static
1842int
1843connect_local_xsocket(unsigned int dnr)
1844{
1845 static const char *const x_sockets[] = {
1846 X_UNIX_PATH "%u",
1847 "/var/X/.X11-unix/X" "%u",
1848 "/usr/spool/sockets/X11/" "%u",
1849 NULL
1850 };
1851 int sock;
1852 struct sockaddr_un addr;
1853 const char *const * path;
1854
1855 for (path = x_sockets; *path; ++path) {
1856 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1857 if (sock < 0)
1858 error("socket: %.100s", strerror(errno));
1859 memset(&addr, 0, sizeof(addr));
1860 addr.sun_family = AF_UNIX;
1861 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
1862 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
1863 return sock;
1864 close(sock);
1865 }
1866 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
1867 return -1;
1868}
1869
1870int
1871x11_connect_display(void)
1872{
1873 int display_number, sock = 0;
1874 const char *display;
1875 char buf[1024], *cp;
1876 struct addrinfo hints, *ai, *aitop;
1877 char strport[NI_MAXSERV];
1878 int gaierr;
1879
1880 /* Try to open a socket for the local X server. */
1881 display = getenv("DISPLAY");
1882 if (!display) {
1883 error("DISPLAY not set.");
1884 return -1;
1885 }
1886 /*
1887 * Now we decode the value of the DISPLAY variable and make a
1888 * connection to the real X server.
1889 */
1890
1891 /*
1892 * Check if it is a unix domain socket. Unix domain displays are in
1893 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
1894 */
1895 if (strncmp(display, "unix:", 5) == 0 ||
1896 display[0] == ':') {
1897 /* Connect to the unix domain socket. */
1898 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
1899 error("Could not parse display number from DISPLAY: %.100s",
1900 display);
1901 return -1;
1902 }
1903 /* Create a socket. */
1904 sock = connect_local_xsocket(display_number);
1905 if (sock < 0)
1906 return -1;
1907
1908 /* OK, we now have a connection to the display. */
1909 return sock;
1910 }
1911 /*
1912 * Connect to an inet socket. The DISPLAY value is supposedly
1913 * hostname:d[.s], where hostname may also be numeric IP address.
1914 */
1915 strncpy(buf, display, sizeof(buf));
1916 buf[sizeof(buf) - 1] = 0;
1917 cp = strchr(buf, ':');
1918 if (!cp) {
1919 error("Could not find ':' in DISPLAY: %.100s", display);
1920 return -1;
1921 }
1922 *cp = 0;
1923 /* buf now contains the host name. But first we parse the display number. */
1924 if (sscanf(cp + 1, "%d", &display_number) != 1) {
1925 error("Could not parse display number from DISPLAY: %.100s",
1926 display);
1927 return -1;
1928 }
1929
1930 /* Look up the host address */
1931 memset(&hints, 0, sizeof(hints));
1932 hints.ai_family = IPv4or6;
1933 hints.ai_socktype = SOCK_STREAM;
1934 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
1935 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
1936 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
1937 return -1;
1938 }
1939 for (ai = aitop; ai; ai = ai->ai_next) {
1940 /* Create a socket. */
1941 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1942 if (sock < 0) {
1943 debug("socket: %.100s", strerror(errno));
1944 continue;
1945 }
1946 /* Connect it to the display. */
1947 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1948 debug("connect %.100s port %d: %.100s", buf,
1949 6000 + display_number, strerror(errno));
1950 close(sock);
1951 continue;
1952 }
1953 /* Success */
1954 break;
1955 }
1956 freeaddrinfo(aitop);
1957 if (!ai) {
1958 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
1959 strerror(errno));
1960 return -1;
1961 }
1962 return sock;
1963}
1964
1965/*
1966 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
1967 * the remote channel number. We should do whatever we want, and respond
1968 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
1969 */
1970
1971void
1972x11_input_open(int type, int plen)
1973{
1974 int remote_channel, sock = 0, newch;
1975 char *remote_host;
1976 unsigned int remote_len;
1977
1978 /* Get remote channel number. */
1979 remote_channel = packet_get_int();
1980
1981 /* Get remote originator name. */
1982 if (have_hostname_in_open) {
1983 remote_host = packet_get_string(&remote_len);
1984 remote_len += 4;
1985 } else {
1986 remote_host = xstrdup("unknown (remote did not supply name)");
1987 remote_len = 0;
1988 }
1989
1990 debug("Received X11 open request.");
1991 packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
1992
1993 /* Obtain a connection to the real X display. */
1994 sock = x11_connect_display();
1995 if (sock == -1) {
1996 /* Send refusal to the remote host. */
1997 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1998 packet_put_int(remote_channel);
1999 packet_send();
2000 } else {
2001 /* Allocate a channel for this connection. */
2002 newch = channel_allocate(
2003 (x11_saved_proto == NULL) ?
2004 SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN,
2005 sock, remote_host);
2006 channels[newch].remote_id = remote_channel;
2007
2008 /* Send a confirmation to the remote host. */
2009 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2010 packet_put_int(remote_channel);
2011 packet_put_int(newch);
2012 packet_send();
2013 }
2014}
2015
2016/*
2017 * Requests forwarding of X11 connections, generates fake authentication
2018 * data, and enables authentication spoofing.
2019 */
2020
2021void
2022x11_request_forwarding_with_spoofing(int client_session_id,
2023 const char *proto, const char *data)
2024{
2025 unsigned int data_len = (unsigned int) strlen(data) / 2;
2026 unsigned int i, value;
2027 char *new_data;
2028 int screen_number;
2029 const char *cp;
2030 u_int32_t rand = 0;
2031
2032 cp = getenv("DISPLAY");
2033 if (cp)
2034 cp = strchr(cp, ':');
2035 if (cp)
2036 cp = strchr(cp, '.');
2037 if (cp)
2038 screen_number = atoi(cp + 1);
2039 else
2040 screen_number = 0;
2041
2042 /* Save protocol name. */
2043 x11_saved_proto = xstrdup(proto);
2044
2045 /*
2046 * Extract real authentication data and generate fake data of the
2047 * same length.
2048 */
2049 x11_saved_data = xmalloc(data_len);
2050 x11_fake_data = xmalloc(data_len);
2051 for (i = 0; i < data_len; i++) {
2052 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2053 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2054 if (i % 4 == 0)
2055 rand = arc4random();
2056 x11_saved_data[i] = value;
2057 x11_fake_data[i] = rand & 0xff;
2058 rand >>= 8;
2059 }
2060 x11_saved_data_len = data_len;
2061 x11_fake_data_len = data_len;
2062
2063 /* Convert the fake data into hex. */
2064 new_data = xmalloc(2 * data_len + 1);
2065 for (i = 0; i < data_len; i++)
2066 sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]);
2067
2068 /* Send the request packet. */
2069 if (compat20) {
2070 channel_request_start(client_session_id, "x11-req", 0);
2071 packet_put_char(0); /* XXX bool single connection */
2072 } else {
2073 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2074 }
2075 packet_put_cstring(proto);
2076 packet_put_cstring(new_data);
2077 packet_put_int(screen_number);
2078 packet_send();
2079 packet_write_wait();
2080 xfree(new_data);
2081}
2082
2083/* Sends a message to the server to request authentication fd forwarding. */
2084
2085void
2086auth_request_forwarding()
2087{
2088 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2089 packet_send();
2090 packet_write_wait();
2091}
2092
2093/*
2094 * Returns the name of the forwarded authentication socket. Returns NULL if
2095 * there is no forwarded authentication socket. The returned value points to
2096 * a static buffer.
2097 */
2098
2099char *
2100auth_get_socket_name()
2101{
2102 return channel_forwarded_auth_socket_name;
2103}
2104
2105/* removes the agent forwarding socket */
2106
2107void
2108cleanup_socket(void)
2109{
2110 remove(channel_forwarded_auth_socket_name);
2111 rmdir(channel_forwarded_auth_socket_dir);
2112}
2113
2114/*
2115 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2116 * This starts forwarding authentication requests.
2117 */
2118
2119int
2120auth_input_request_forwarding(struct passwd * pw)
2121{
2122 int sock, newch;
2123 struct sockaddr_un sunaddr;
2124
2125 if (auth_get_socket_name() != NULL)
2126 fatal("Protocol error: authentication forwarding requested twice.");
2127
2128 /* Temporarily drop privileged uid for mkdir/bind. */
2129 temporarily_use_uid(pw->pw_uid);
2130
2131 /* Allocate a buffer for the socket name, and format the name. */
2132 channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
2133 channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
2134 strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
2135
2136 /* Create private directory for socket */
2137 if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL) {
2138 packet_send_debug("Agent forwarding disabled: mkdtemp() failed: %.100s",
2139 strerror(errno));
2140 restore_uid();
2141 xfree(channel_forwarded_auth_socket_name);
2142 xfree(channel_forwarded_auth_socket_dir);
2143 channel_forwarded_auth_socket_name = NULL;
2144 channel_forwarded_auth_socket_dir = NULL;
2145 return 0;
2146 }
2147 snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
2148 channel_forwarded_auth_socket_dir, (int) getpid());
2149
2150 if (atexit(cleanup_socket) < 0) {
2151 int saved = errno;
2152 cleanup_socket();
2153 packet_disconnect("socket: %.100s", strerror(saved));
2154 }
2155 /* Create the socket. */
2156 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2157 if (sock < 0)
2158 packet_disconnect("socket: %.100s", strerror(errno));
2159
2160 /* Bind it to the name. */
2161 memset(&sunaddr, 0, sizeof(sunaddr));
2162 sunaddr.sun_family = AF_UNIX;
2163 strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
2164 sizeof(sunaddr.sun_path));
2165
2166 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2167 packet_disconnect("bind: %.100s", strerror(errno));
2168
2169 /* Restore the privileged uid. */
2170 restore_uid();
2171
2172 /* Start listening on the socket. */
2173 if (listen(sock, 5) < 0)
2174 packet_disconnect("listen: %.100s", strerror(errno));
2175
2176 /* Allocate a channel for the authentication agent socket. */
2177 newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock,
2178 xstrdup("auth socket"));
2179 strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
2180 sizeof(channels[newch].path));
2181 return 1;
2182}
2183
2184/* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2185
2186void
2187auth_input_open_request(int type, int plen)
2188{
2189 int remch, sock, newch;
2190 char *dummyname;
2191
2192 packet_integrity_check(plen, 4, type);
2193
2194 /* Read the remote channel number from the message. */
2195 remch = packet_get_int();
2196
2197 /*
2198 * Get a connection to the local authentication agent (this may again
2199 * get forwarded).
2200 */
2201 sock = ssh_get_authentication_socket();
2202
2203 /*
2204 * If we could not connect the agent, send an error message back to
2205 * the server. This should never happen unless the agent dies,
2206 * because authentication forwarding is only enabled if we have an
2207 * agent.
2208 */
2209 if (sock < 0) {
2210 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2211 packet_put_int(remch);
2212 packet_send();
2213 return;
2214 }
2215 debug("Forwarding authentication connection.");
2216
2217 /*
2218 * Dummy host name. This will be freed when the channel is freed; it
2219 * will still be valid in the packet_put_string below since the
2220 * channel cannot yet be freed at that point.
2221 */
2222 dummyname = xstrdup("authentication agent connection");
2223
2224 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
2225 channels[newch].remote_id = remch;
2226
2227 /* Send a confirmation to the remote host. */
2228 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2229 packet_put_int(remch);
2230 packet_put_int(newch);
2231 packet_send();
2232}
2233
2234void
2235channel_start_open(int id)
2236{
2237 Channel *c = channel_lookup(id);
2238 if (c == NULL) {
2239 log("channel_open: %d: bad id", id);
2240 return;
2241 }
2242 debug("send channel open %d", id);
2243 packet_start(SSH2_MSG_CHANNEL_OPEN);
2244 packet_put_cstring(c->ctype);
2245 packet_put_int(c->self);
2246 packet_put_int(c->local_window);
2247 packet_put_int(c->local_maxpacket);
2248}
2249void
2250channel_open(int id)
2251{
2252 /* XXX REMOVE ME */
2253 channel_start_open(id);
2254 packet_send();
2255}
2256void
2257channel_request(int id, char *service, int wantconfirm)
2258{
2259 channel_request_start(id, service, wantconfirm);
2260 packet_send();
2261 debug("channel request %d: %s", id, service) ;
2262}
2263void
2264channel_request_start(int id, char *service, int wantconfirm)
2265{
2266 Channel *c = channel_lookup(id);
2267 if (c == NULL) {
2268 log("channel_request: %d: bad id", id);
2269 return;
2270 }
2271 packet_start(SSH2_MSG_CHANNEL_REQUEST);
2272 packet_put_int(c->remote_id);
2273 packet_put_cstring(service);
2274 packet_put_char(wantconfirm);
2275}
2276void
2277channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
2278{
2279 Channel *c = channel_lookup(id);
2280 if (c == NULL) {
2281 log("channel_register_callback: %d: bad id", id);
2282 return;
2283 }
2284 c->cb_event = mtype;
2285 c->cb_fn = fn;
2286 c->cb_arg = arg;
2287}
2288void
2289channel_register_cleanup(int id, channel_callback_fn *fn)
2290{
2291 Channel *c = channel_lookup(id);
2292 if (c == NULL) {
2293 log("channel_register_cleanup: %d: bad id", id);
2294 return;
2295 }
2296 c->dettach_user = fn;
2297}
2298void
2299channel_cancel_cleanup(int id)
2300{
2301 Channel *c = channel_lookup(id);
2302 if (c == NULL) {
2303 log("channel_cancel_cleanup: %d: bad id", id);
2304 return;
2305 }
2306 c->dettach_user = NULL;
2307}
2308
2309void
2310channel_set_fds(int id, int rfd, int wfd, int efd, int extusage)
2311{
2312 Channel *c = channel_lookup(id);
2313 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
2314 fatal("channel_activate for non-larval channel %d.", id);
2315
2316 channel_register_fds(c, rfd, wfd, efd, extusage);
2317 c->type = SSH_CHANNEL_OPEN;
2318 /* XXX window size? */
2319 c->local_window = c->local_window_max = c->local_maxpacket/2;
2320 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2321 packet_put_int(c->remote_id);
2322 packet_put_int(c->local_window);
2323 packet_send();
2324}