1 /* $OpenBSD: channels.c,v 1.282 2008/06/16 13:22:53 dtucker Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
47 #include <sys/socket.h>
48 #ifdef HAVE_SYS_TIME_H
49 # include <sys/time.h>
52 #include <netinet/in.h>
53 #include <arpa/inet.h>
64 #include "openbsd-compat/sys-queue.h"
78 #include "pathnames.h"
83 * Pointer to an array containing all allocated channels. The array is
84 * dynamically extended as needed.
86 static Channel **channels = NULL;
89 * Size of the channel array. All slots of the array must always be
90 * initialized (at least the type field); unused slots set to NULL
92 static u_int channels_alloc = 0;
95 * Maximum file descriptor value used in any of the channels. This is
96 * updated in channel_new.
98 static int channel_max_fd = 0;
101 /* -- tcp forwarding */
104 * Data structure for storing which hosts are permitted for forward requests.
105 * The local sides of any remote forwards are stored in this array to prevent
106 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
107 * network (which might be behind a firewall).
110 char *host_to_connect; /* Connect to 'host'. */
111 u_short port_to_connect; /* Connect to 'port'. */
112 u_short listen_port; /* Remote side should listen port number. */
115 /* List of all permitted host/port pairs to connect by the user. */
116 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
118 /* List of all permitted host/port pairs to connect by the admin. */
119 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
121 /* Number of permitted host/port pairs in the array permitted by the user. */
122 static int num_permitted_opens = 0;
124 /* Number of permitted host/port pair in the array permitted by the admin. */
125 static int num_adm_permitted_opens = 0;
128 * If this is true, all opens are permitted. This is the case on the server
129 * on which we have to trust the client anyway, and the user could do
130 * anything after logging in anyway.
132 static int all_opens_permitted = 0;
135 /* -- X11 forwarding */
137 /* Maximum number of fake X11 displays to try. */
138 #define MAX_DISPLAYS 1000
140 /* Saved X11 local (client) display. */
141 static char *x11_saved_display = NULL;
143 /* Saved X11 authentication protocol name. */
144 static char *x11_saved_proto = NULL;
146 /* Saved X11 authentication data. This is the real data. */
147 static char *x11_saved_data = NULL;
148 static u_int x11_saved_data_len = 0;
151 * Fake X11 authentication data. This is what the server will be sending us;
152 * we should replace any occurrences of this by the real data.
154 static u_char *x11_fake_data = NULL;
155 static u_int x11_fake_data_len;
158 /* -- agent forwarding */
162 /* AF_UNSPEC or AF_INET or AF_INET6 */
163 static int IPv4or6 = AF_UNSPEC;
166 static void port_open_helper(Channel *c, char *rtype);
168 /* non-blocking connect helpers */
169 static int connect_next(struct channel_connect *);
170 static void channel_connect_ctx_free(struct channel_connect *);
172 /* -- channel core */
175 channel_by_id(int id)
179 if (id < 0 || (u_int)id >= channels_alloc) {
180 logit("channel_by_id: %d: bad id", id);
185 logit("channel_by_id: %d: bad id: channel free", id);
192 * Returns the channel if it is allowed to receive protocol messages.
193 * Private channels, like listening sockets, may not receive messages.
196 channel_lookup(int id)
200 if ((c = channel_by_id(id)) == NULL)
204 case SSH_CHANNEL_X11_OPEN:
205 case SSH_CHANNEL_LARVAL:
206 case SSH_CHANNEL_CONNECTING:
207 case SSH_CHANNEL_DYNAMIC:
208 case SSH_CHANNEL_OPENING:
209 case SSH_CHANNEL_OPEN:
210 case SSH_CHANNEL_INPUT_DRAINING:
211 case SSH_CHANNEL_OUTPUT_DRAINING:
214 logit("Non-public channel %d, type %d.", id, c->type);
219 * Register filedescriptors for a channel, used when allocating a channel or
220 * when the channel consumer/producer is ready, e.g. shell exec'd
223 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
224 int extusage, int nonblock, int is_tty)
226 /* Update the maximum file descriptor value. */
227 channel_max_fd = MAX(channel_max_fd, rfd);
228 channel_max_fd = MAX(channel_max_fd, wfd);
229 channel_max_fd = MAX(channel_max_fd, efd);
231 /* XXX set close-on-exec -markus */
235 c->sock = (rfd == wfd) ? rfd : -1;
236 c->ctl_fd = -1; /* XXX: set elsewhere */
238 c->extended_usage = extusage;
240 if ((c->isatty = is_tty) != 0)
241 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
242 c->wfd_isatty = isatty || isatty(c->wfd);
244 /* enable nonblocking mode */
256 * Allocate a new channel object and set its type and socket. This will cause
257 * remote_name to be freed.
260 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
261 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
267 /* Do initial allocation if this is the first call. */
268 if (channels_alloc == 0) {
270 channels = xcalloc(channels_alloc, sizeof(Channel *));
271 for (i = 0; i < channels_alloc; i++)
274 /* Try to find a free slot where to put the new channel. */
275 for (found = -1, i = 0; i < channels_alloc; i++)
276 if (channels[i] == NULL) {
277 /* Found a free slot. */
282 /* There are no free slots. Take last+1 slot and expand the array. */
283 found = channels_alloc;
284 if (channels_alloc > 10000)
285 fatal("channel_new: internal error: channels_alloc %d "
286 "too big.", channels_alloc);
287 channels = xrealloc(channels, channels_alloc + 10,
289 channels_alloc += 10;
290 debug2("channel: expanding %d", channels_alloc);
291 for (i = found; i < channels_alloc; i++)
294 /* Initialize and return new channel. */
295 c = channels[found] = xcalloc(1, sizeof(Channel));
296 buffer_init(&c->input);
297 buffer_init(&c->output);
298 buffer_init(&c->extended);
299 c->ostate = CHAN_OUTPUT_OPEN;
300 c->istate = CHAN_INPUT_OPEN;
302 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
306 c->local_window = window;
307 c->local_window_max = window;
308 c->local_consumed = 0;
309 c->local_maxpacket = maxpack;
311 c->remote_name = xstrdup(remote_name);
312 c->remote_window = 0;
313 c->remote_maxpacket = 0;
315 c->single_connection = 0;
316 c->detach_user = NULL;
318 c->open_confirm = NULL;
319 c->open_confirm_ctx = NULL;
320 c->input_filter = NULL;
321 c->output_filter = NULL;
322 c->filter_ctx = NULL;
323 c->filter_cleanup = NULL;
324 TAILQ_INIT(&c->status_confirms);
325 debug("channel %d: new [%s]", found, remote_name);
330 channel_find_maxfd(void)
336 for (i = 0; i < channels_alloc; i++) {
339 max = MAX(max, c->rfd);
340 max = MAX(max, c->wfd);
341 max = MAX(max, c->efd);
348 channel_close_fd(int *fdp)
350 int ret = 0, fd = *fdp;
355 if (fd == channel_max_fd)
356 channel_max_fd = channel_find_maxfd();
361 /* Close all channel fd/socket. */
363 channel_close_fds(Channel *c)
365 debug3("channel %d: close_fds r %d w %d e %d c %d",
366 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
368 channel_close_fd(&c->sock);
369 channel_close_fd(&c->ctl_fd);
370 channel_close_fd(&c->rfd);
371 channel_close_fd(&c->wfd);
372 channel_close_fd(&c->efd);
375 /* Free the channel and close its fd/socket. */
377 channel_free(Channel *c)
381 struct channel_confirm *cc;
383 for (n = 0, i = 0; i < channels_alloc; i++)
386 debug("channel %d: free: %s, nchannels %u", c->self,
387 c->remote_name ? c->remote_name : "???", n);
389 s = channel_open_message();
390 debug3("channel %d: status: %s", c->self, s);
394 shutdown(c->sock, SHUT_RDWR);
396 shutdown(c->ctl_fd, SHUT_RDWR);
397 channel_close_fds(c);
398 buffer_free(&c->input);
399 buffer_free(&c->output);
400 buffer_free(&c->extended);
401 if (c->remote_name) {
402 xfree(c->remote_name);
403 c->remote_name = NULL;
405 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
406 if (cc->abandon_cb != NULL)
407 cc->abandon_cb(c, cc->ctx);
408 TAILQ_REMOVE(&c->status_confirms, cc, entry);
409 bzero(cc, sizeof(*cc));
412 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
413 c->filter_cleanup(c->self, c->filter_ctx);
414 channels[c->self] = NULL;
419 channel_free_all(void)
423 for (i = 0; i < channels_alloc; i++)
424 if (channels[i] != NULL)
425 channel_free(channels[i]);
429 * Closes the sockets/fds of all channels. This is used to close extra file
430 * descriptors after a fork.
433 channel_close_all(void)
437 for (i = 0; i < channels_alloc; i++)
438 if (channels[i] != NULL)
439 channel_close_fds(channels[i]);
443 * Stop listening to channels.
446 channel_stop_listening(void)
451 for (i = 0; i < channels_alloc; i++) {
455 case SSH_CHANNEL_AUTH_SOCKET:
456 case SSH_CHANNEL_PORT_LISTENER:
457 case SSH_CHANNEL_RPORT_LISTENER:
458 case SSH_CHANNEL_X11_LISTENER:
459 channel_close_fd(&c->sock);
468 * Returns true if no channel has too much buffered data, and false if one or
469 * more channel is overfull.
472 channel_not_very_much_buffered_data(void)
477 for (i = 0; i < channels_alloc; i++) {
479 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
482 buffer_len(&c->input) > packet_get_maxsize()) {
483 debug2("channel %d: big input buffer %d",
484 c->self, buffer_len(&c->input));
488 if (buffer_len(&c->output) > packet_get_maxsize()) {
489 debug2("channel %d: big output buffer %u > %u",
490 c->self, buffer_len(&c->output),
491 packet_get_maxsize());
499 /* Returns true if any channel is still open. */
501 channel_still_open(void)
506 for (i = 0; i < channels_alloc; i++) {
511 case SSH_CHANNEL_X11_LISTENER:
512 case SSH_CHANNEL_PORT_LISTENER:
513 case SSH_CHANNEL_RPORT_LISTENER:
514 case SSH_CHANNEL_CLOSED:
515 case SSH_CHANNEL_AUTH_SOCKET:
516 case SSH_CHANNEL_DYNAMIC:
517 case SSH_CHANNEL_CONNECTING:
518 case SSH_CHANNEL_ZOMBIE:
520 case SSH_CHANNEL_LARVAL:
522 fatal("cannot happen: SSH_CHANNEL_LARVAL");
524 case SSH_CHANNEL_OPENING:
525 case SSH_CHANNEL_OPEN:
526 case SSH_CHANNEL_X11_OPEN:
528 case SSH_CHANNEL_INPUT_DRAINING:
529 case SSH_CHANNEL_OUTPUT_DRAINING:
531 fatal("cannot happen: OUT_DRAIN");
534 fatal("channel_still_open: bad channel type %d", c->type);
541 /* Returns the id of an open channel suitable for keepaliving */
543 channel_find_open(void)
548 for (i = 0; i < channels_alloc; i++) {
550 if (c == NULL || c->remote_id < 0)
553 case SSH_CHANNEL_CLOSED:
554 case SSH_CHANNEL_DYNAMIC:
555 case SSH_CHANNEL_X11_LISTENER:
556 case SSH_CHANNEL_PORT_LISTENER:
557 case SSH_CHANNEL_RPORT_LISTENER:
558 case SSH_CHANNEL_OPENING:
559 case SSH_CHANNEL_CONNECTING:
560 case SSH_CHANNEL_ZOMBIE:
562 case SSH_CHANNEL_LARVAL:
563 case SSH_CHANNEL_AUTH_SOCKET:
564 case SSH_CHANNEL_OPEN:
565 case SSH_CHANNEL_X11_OPEN:
567 case SSH_CHANNEL_INPUT_DRAINING:
568 case SSH_CHANNEL_OUTPUT_DRAINING:
570 fatal("cannot happen: OUT_DRAIN");
573 fatal("channel_find_open: bad channel type %d", c->type);
582 * Returns a message describing the currently open forwarded connections,
583 * suitable for sending to the client. The message contains crlf pairs for
587 channel_open_message(void)
594 buffer_init(&buffer);
595 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
596 buffer_append(&buffer, buf, strlen(buf));
597 for (i = 0; i < channels_alloc; i++) {
602 case SSH_CHANNEL_X11_LISTENER:
603 case SSH_CHANNEL_PORT_LISTENER:
604 case SSH_CHANNEL_RPORT_LISTENER:
605 case SSH_CHANNEL_CLOSED:
606 case SSH_CHANNEL_AUTH_SOCKET:
607 case SSH_CHANNEL_ZOMBIE:
609 case SSH_CHANNEL_LARVAL:
610 case SSH_CHANNEL_OPENING:
611 case SSH_CHANNEL_CONNECTING:
612 case SSH_CHANNEL_DYNAMIC:
613 case SSH_CHANNEL_OPEN:
614 case SSH_CHANNEL_X11_OPEN:
615 case SSH_CHANNEL_INPUT_DRAINING:
616 case SSH_CHANNEL_OUTPUT_DRAINING:
617 snprintf(buf, sizeof buf,
618 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
619 c->self, c->remote_name,
620 c->type, c->remote_id,
621 c->istate, buffer_len(&c->input),
622 c->ostate, buffer_len(&c->output),
623 c->rfd, c->wfd, c->ctl_fd);
624 buffer_append(&buffer, buf, strlen(buf));
627 fatal("channel_open_message: bad channel type %d", c->type);
631 buffer_append(&buffer, "\0", 1);
632 cp = xstrdup(buffer_ptr(&buffer));
633 buffer_free(&buffer);
638 channel_send_open(int id)
640 Channel *c = channel_lookup(id);
643 logit("channel_send_open: %d: bad id", id);
646 debug2("channel %d: send open", id);
647 packet_start(SSH2_MSG_CHANNEL_OPEN);
648 packet_put_cstring(c->ctype);
649 packet_put_int(c->self);
650 packet_put_int(c->local_window);
651 packet_put_int(c->local_maxpacket);
656 channel_request_start(int id, char *service, int wantconfirm)
658 Channel *c = channel_lookup(id);
661 logit("channel_request_start: %d: unknown channel id", id);
664 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
665 packet_start(SSH2_MSG_CHANNEL_REQUEST);
666 packet_put_int(c->remote_id);
667 packet_put_cstring(service);
668 packet_put_char(wantconfirm);
672 channel_register_status_confirm(int id, channel_confirm_cb *cb,
673 channel_confirm_abandon_cb *abandon_cb, void *ctx)
675 struct channel_confirm *cc;
678 if ((c = channel_lookup(id)) == NULL)
679 fatal("channel_register_expect: %d: bad id", id);
681 cc = xmalloc(sizeof(*cc));
683 cc->abandon_cb = abandon_cb;
685 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
689 channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
691 Channel *c = channel_lookup(id);
694 logit("channel_register_open_comfirm: %d: bad id", id);
697 c->open_confirm = fn;
698 c->open_confirm_ctx = ctx;
702 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
704 Channel *c = channel_by_id(id);
707 logit("channel_register_cleanup: %d: bad id", id);
711 c->detach_close = do_close;
715 channel_cancel_cleanup(int id)
717 Channel *c = channel_by_id(id);
720 logit("channel_cancel_cleanup: %d: bad id", id);
723 c->detach_user = NULL;
728 channel_register_filter(int id, channel_infilter_fn *ifn,
729 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
731 Channel *c = channel_lookup(id);
734 logit("channel_register_filter: %d: bad id", id);
737 c->input_filter = ifn;
738 c->output_filter = ofn;
740 c->filter_cleanup = cfn;
744 channel_set_fds(int id, int rfd, int wfd, int efd,
745 int extusage, int nonblock, int is_tty, u_int window_max)
747 Channel *c = channel_lookup(id);
749 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
750 fatal("channel_activate for non-larval channel %d.", id);
751 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
752 c->type = SSH_CHANNEL_OPEN;
753 c->local_window = c->local_window_max = window_max;
754 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
755 packet_put_int(c->remote_id);
756 packet_put_int(c->local_window);
761 * 'channel_pre*' are called just before select() to add any bits relevant to
762 * channels in the select bitmasks.
765 * 'channel_post*': perform any appropriate operations for channels which
766 * have events pending.
768 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
769 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
770 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
774 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
776 FD_SET(c->sock, readset);
781 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
783 debug3("channel %d: waiting for connection", c->self);
784 FD_SET(c->sock, writeset);
788 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
790 if (buffer_len(&c->input) < packet_get_maxsize())
791 FD_SET(c->sock, readset);
792 if (buffer_len(&c->output) > 0)
793 FD_SET(c->sock, writeset);
797 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
799 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
801 if (c->istate == CHAN_INPUT_OPEN &&
803 buffer_len(&c->input) < limit &&
804 buffer_check_alloc(&c->input, CHAN_RBUF))
805 FD_SET(c->rfd, readset);
806 if (c->ostate == CHAN_OUTPUT_OPEN ||
807 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
808 if (buffer_len(&c->output) > 0) {
809 FD_SET(c->wfd, writeset);
810 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
811 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
812 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
813 c->self, c->efd, buffer_len(&c->extended));
818 /** XXX check close conditions, too */
819 if (compat20 && c->efd != -1 &&
820 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
821 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
822 buffer_len(&c->extended) > 0)
823 FD_SET(c->efd, writeset);
824 else if (!(c->flags & CHAN_EOF_SENT) &&
825 c->extended_usage == CHAN_EXTENDED_READ &&
826 buffer_len(&c->extended) < c->remote_window)
827 FD_SET(c->efd, readset);
829 /* XXX: What about efd? races? */
830 if (compat20 && c->ctl_fd != -1 &&
831 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
832 FD_SET(c->ctl_fd, readset);
837 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
839 if (buffer_len(&c->input) == 0) {
840 packet_start(SSH_MSG_CHANNEL_CLOSE);
841 packet_put_int(c->remote_id);
843 c->type = SSH_CHANNEL_CLOSED;
844 debug2("channel %d: closing after input drain.", c->self);
850 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
852 if (buffer_len(&c->output) == 0)
855 FD_SET(c->sock, writeset);
859 * This is a special state for X11 authentication spoofing. An opened X11
860 * connection (when authentication spoofing is being done) remains in this
861 * state until the first packet has been completely read. The authentication
862 * data in that packet is then substituted by the real data if it matches the
863 * fake data, and the channel is put into normal mode.
864 * XXX All this happens at the client side.
865 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
868 x11_open_helper(Buffer *b)
871 u_int proto_len, data_len;
873 /* Check if the fixed size part of the packet is in buffer. */
874 if (buffer_len(b) < 12)
877 /* Parse the lengths of variable-length fields. */
879 if (ucp[0] == 0x42) { /* Byte order MSB first. */
880 proto_len = 256 * ucp[6] + ucp[7];
881 data_len = 256 * ucp[8] + ucp[9];
882 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
883 proto_len = ucp[6] + 256 * ucp[7];
884 data_len = ucp[8] + 256 * ucp[9];
886 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
891 /* Check if the whole packet is in buffer. */
893 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
896 /* Check if authentication protocol matches. */
897 if (proto_len != strlen(x11_saved_proto) ||
898 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
899 debug2("X11 connection uses different authentication protocol.");
902 /* Check if authentication data matches our fake data. */
903 if (data_len != x11_fake_data_len ||
904 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
905 x11_fake_data, x11_fake_data_len) != 0) {
906 debug2("X11 auth data does not match fake data.");
909 /* Check fake data length */
910 if (x11_fake_data_len != x11_saved_data_len) {
911 error("X11 fake_data_len %d != saved_data_len %d",
912 x11_fake_data_len, x11_saved_data_len);
916 * Received authentication protocol and data match
917 * our fake data. Substitute the fake data with real
920 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
921 x11_saved_data, x11_saved_data_len);
926 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
928 int ret = x11_open_helper(&c->output);
931 /* Start normal processing for the channel. */
932 c->type = SSH_CHANNEL_OPEN;
933 channel_pre_open_13(c, readset, writeset);
934 } else if (ret == -1) {
936 * We have received an X11 connection that has bad
937 * authentication information.
939 logit("X11 connection rejected because of wrong authentication.");
940 buffer_clear(&c->input);
941 buffer_clear(&c->output);
942 channel_close_fd(&c->sock);
944 c->type = SSH_CHANNEL_CLOSED;
945 packet_start(SSH_MSG_CHANNEL_CLOSE);
946 packet_put_int(c->remote_id);
952 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
954 int ret = x11_open_helper(&c->output);
956 /* c->force_drain = 1; */
959 c->type = SSH_CHANNEL_OPEN;
960 channel_pre_open(c, readset, writeset);
961 } else if (ret == -1) {
962 logit("X11 connection rejected because of wrong authentication.");
963 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
965 buffer_clear(&c->input);
967 buffer_clear(&c->output);
968 /* for proto v1, the peer will send an IEOF */
970 chan_write_failed(c);
972 c->type = SSH_CHANNEL_OPEN;
973 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
977 /* try to decode a socks4 header */
980 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
983 u_int len, have, i, found;
989 struct in_addr dest_addr;
992 debug2("channel %d: decode socks4", c->self);
994 have = buffer_len(&c->input);
995 len = sizeof(s4_req);
998 p = buffer_ptr(&c->input);
999 for (found = 0, i = len; i < have; i++) {
1005 /* the peer is probably sending garbage */
1006 debug("channel %d: decode socks4: too long",
1013 buffer_get(&c->input, (char *)&s4_req.version, 1);
1014 buffer_get(&c->input, (char *)&s4_req.command, 1);
1015 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1016 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1017 have = buffer_len(&c->input);
1018 p = buffer_ptr(&c->input);
1020 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1022 fatal("channel %d: decode socks4: len %d > have %d",
1023 c->self, len, have);
1024 strlcpy(username, p, sizeof(username));
1025 buffer_consume(&c->input, len);
1026 buffer_consume(&c->input, 1); /* trailing '\0' */
1028 host = inet_ntoa(s4_req.dest_addr);
1029 strlcpy(c->path, host, sizeof(c->path));
1030 c->host_port = ntohs(s4_req.dest_port);
1032 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1033 c->self, host, c->host_port, s4_req.command);
1035 if (s4_req.command != 1) {
1036 debug("channel %d: cannot handle: socks4 cn %d",
1037 c->self, s4_req.command);
1040 s4_rsp.version = 0; /* vn: 0 for reply */
1041 s4_rsp.command = 90; /* cd: req granted */
1042 s4_rsp.dest_port = 0; /* ignored */
1043 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1044 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1048 /* try to decode a socks5 header */
1049 #define SSH_SOCKS5_AUTHDONE 0x1000
1050 #define SSH_SOCKS5_NOAUTH 0x00
1051 #define SSH_SOCKS5_IPV4 0x01
1052 #define SSH_SOCKS5_DOMAIN 0x03
1053 #define SSH_SOCKS5_IPV6 0x04
1054 #define SSH_SOCKS5_CONNECT 0x01
1055 #define SSH_SOCKS5_SUCCESS 0x00
1059 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1067 u_int16_t dest_port;
1068 u_char *p, dest_addr[255+1];
1069 u_int have, need, i, found, nmethods, addrlen, af;
1071 debug2("channel %d: decode socks5", c->self);
1072 p = buffer_ptr(&c->input);
1075 have = buffer_len(&c->input);
1076 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1077 /* format: ver | nmethods | methods */
1081 if (have < nmethods + 2)
1083 /* look for method: "NO AUTHENTICATION REQUIRED" */
1084 for (found = 0, i = 2; i < nmethods + 2; i++) {
1085 if (p[i] == SSH_SOCKS5_NOAUTH) {
1091 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1095 buffer_consume(&c->input, nmethods + 2);
1096 buffer_put_char(&c->output, 0x05); /* version */
1097 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1098 FD_SET(c->sock, writeset);
1099 c->flags |= SSH_SOCKS5_AUTHDONE;
1100 debug2("channel %d: socks5 auth done", c->self);
1101 return 0; /* need more */
1103 debug2("channel %d: socks5 post auth", c->self);
1104 if (have < sizeof(s5_req)+1)
1105 return 0; /* need more */
1106 memcpy(&s5_req, p, sizeof(s5_req));
1107 if (s5_req.version != 0x05 ||
1108 s5_req.command != SSH_SOCKS5_CONNECT ||
1109 s5_req.reserved != 0x00) {
1110 debug2("channel %d: only socks5 connect supported", c->self);
1113 switch (s5_req.atyp){
1114 case SSH_SOCKS5_IPV4:
1118 case SSH_SOCKS5_DOMAIN:
1119 addrlen = p[sizeof(s5_req)];
1122 case SSH_SOCKS5_IPV6:
1127 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1130 need = sizeof(s5_req) + addrlen + 2;
1131 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1135 buffer_consume(&c->input, sizeof(s5_req));
1136 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1137 buffer_consume(&c->input, 1); /* host string length */
1138 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1139 buffer_get(&c->input, (char *)&dest_port, 2);
1140 dest_addr[addrlen] = '\0';
1141 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1142 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1143 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1145 c->host_port = ntohs(dest_port);
1147 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1148 c->self, c->path, c->host_port, s5_req.command);
1150 s5_rsp.version = 0x05;
1151 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1152 s5_rsp.reserved = 0; /* ignored */
1153 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1154 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1155 dest_port = 0; /* ignored */
1157 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1158 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1159 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1163 /* dynamic port forwarding */
1165 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1171 have = buffer_len(&c->input);
1173 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1174 /* buffer_dump(&c->input); */
1175 /* check if the fixed size part of the packet is in buffer. */
1178 FD_SET(c->sock, readset);
1181 /* try to guess the protocol */
1182 p = buffer_ptr(&c->input);
1185 ret = channel_decode_socks4(c, readset, writeset);
1188 ret = channel_decode_socks5(c, readset, writeset);
1196 } else if (ret == 0) {
1197 debug2("channel %d: pre_dynamic: need more", c->self);
1199 FD_SET(c->sock, readset);
1201 /* switch to the next state */
1202 c->type = SSH_CHANNEL_OPENING;
1203 port_open_helper(c, "direct-tcpip");
1207 /* This is our fake X11 server socket. */
1210 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1213 struct sockaddr addr;
1216 char buf[16384], *remote_ipaddr;
1219 if (FD_ISSET(c->sock, readset)) {
1220 debug("X11 connection requested.");
1221 addrlen = sizeof(addr);
1222 newsock = accept(c->sock, &addr, &addrlen);
1223 if (c->single_connection) {
1224 debug2("single_connection: closing X11 listener.");
1225 channel_close_fd(&c->sock);
1229 error("accept: %.100s", strerror(errno));
1232 set_nodelay(newsock);
1233 remote_ipaddr = get_peer_ipaddr(newsock);
1234 remote_port = get_peer_port(newsock);
1235 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1236 remote_ipaddr, remote_port);
1238 nc = channel_new("accepted x11 socket",
1239 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1240 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1242 packet_start(SSH2_MSG_CHANNEL_OPEN);
1243 packet_put_cstring("x11");
1244 packet_put_int(nc->self);
1245 packet_put_int(nc->local_window_max);
1246 packet_put_int(nc->local_maxpacket);
1247 /* originator ipaddr and port */
1248 packet_put_cstring(remote_ipaddr);
1249 if (datafellows & SSH_BUG_X11FWD) {
1250 debug2("ssh2 x11 bug compat mode");
1252 packet_put_int(remote_port);
1256 packet_start(SSH_SMSG_X11_OPEN);
1257 packet_put_int(nc->self);
1258 if (packet_get_protocol_flags() &
1259 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1260 packet_put_cstring(buf);
1263 xfree(remote_ipaddr);
1268 port_open_helper(Channel *c, char *rtype)
1272 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1273 int remote_port = get_peer_port(c->sock);
1275 direct = (strcmp(rtype, "direct-tcpip") == 0);
1277 snprintf(buf, sizeof buf,
1278 "%s: listening port %d for %.100s port %d, "
1279 "connect from %.200s port %d",
1280 rtype, c->listening_port, c->path, c->host_port,
1281 remote_ipaddr, remote_port);
1283 xfree(c->remote_name);
1284 c->remote_name = xstrdup(buf);
1287 packet_start(SSH2_MSG_CHANNEL_OPEN);
1288 packet_put_cstring(rtype);
1289 packet_put_int(c->self);
1290 packet_put_int(c->local_window_max);
1291 packet_put_int(c->local_maxpacket);
1293 /* target host, port */
1294 packet_put_cstring(c->path);
1295 packet_put_int(c->host_port);
1297 /* listen address, port */
1298 packet_put_cstring(c->path);
1299 packet_put_int(c->listening_port);
1301 /* originator host and port */
1302 packet_put_cstring(remote_ipaddr);
1303 packet_put_int((u_int)remote_port);
1306 packet_start(SSH_MSG_PORT_OPEN);
1307 packet_put_int(c->self);
1308 packet_put_cstring(c->path);
1309 packet_put_int(c->host_port);
1310 if (packet_get_protocol_flags() &
1311 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1312 packet_put_cstring(c->remote_name);
1315 xfree(remote_ipaddr);
1319 channel_set_reuseaddr(int fd)
1324 * Set socket options.
1325 * Allow local port reuse in TIME_WAIT.
1327 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1328 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1332 * This socket is listening for connections to a forwarded TCP/IP port.
1336 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1339 struct sockaddr addr;
1340 int newsock, nextstate;
1344 if (FD_ISSET(c->sock, readset)) {
1345 debug("Connection to port %d forwarding "
1346 "to %.100s port %d requested.",
1347 c->listening_port, c->path, c->host_port);
1349 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1350 nextstate = SSH_CHANNEL_OPENING;
1351 rtype = "forwarded-tcpip";
1353 if (c->host_port == 0) {
1354 nextstate = SSH_CHANNEL_DYNAMIC;
1355 rtype = "dynamic-tcpip";
1357 nextstate = SSH_CHANNEL_OPENING;
1358 rtype = "direct-tcpip";
1362 addrlen = sizeof(addr);
1363 newsock = accept(c->sock, &addr, &addrlen);
1365 error("accept: %.100s", strerror(errno));
1368 set_nodelay(newsock);
1369 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1370 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1371 nc->listening_port = c->listening_port;
1372 nc->host_port = c->host_port;
1373 strlcpy(nc->path, c->path, sizeof(nc->path));
1375 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1377 * do not call the channel_post handler until
1378 * this flag has been reset by a pre-handler.
1379 * otherwise the FD_ISSET calls might overflow
1383 port_open_helper(nc, rtype);
1389 * This is the authentication agent socket listening for connections from
1394 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1398 struct sockaddr addr;
1401 if (FD_ISSET(c->sock, readset)) {
1402 addrlen = sizeof(addr);
1403 newsock = accept(c->sock, &addr, &addrlen);
1405 error("accept from auth socket: %.100s", strerror(errno));
1408 nc = channel_new("accepted auth socket",
1409 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1410 c->local_window_max, c->local_maxpacket,
1411 0, "accepted auth socket", 1);
1413 packet_start(SSH2_MSG_CHANNEL_OPEN);
1414 packet_put_cstring("auth-agent@openssh.com");
1415 packet_put_int(nc->self);
1416 packet_put_int(c->local_window_max);
1417 packet_put_int(c->local_maxpacket);
1419 packet_start(SSH_SMSG_AGENT_OPEN);
1420 packet_put_int(nc->self);
1428 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1431 socklen_t sz = sizeof(err);
1433 if (FD_ISSET(c->sock, writeset)) {
1434 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1436 error("getsockopt SO_ERROR failed");
1439 debug("channel %d: connected to %s port %d",
1440 c->self, c->connect_ctx.host, c->connect_ctx.port);
1441 channel_connect_ctx_free(&c->connect_ctx);
1442 c->type = SSH_CHANNEL_OPEN;
1444 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1445 packet_put_int(c->remote_id);
1446 packet_put_int(c->self);
1447 packet_put_int(c->local_window);
1448 packet_put_int(c->local_maxpacket);
1450 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1451 packet_put_int(c->remote_id);
1452 packet_put_int(c->self);
1455 debug("channel %d: connection failed: %s",
1456 c->self, strerror(err));
1457 /* Try next address, if any */
1458 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1460 c->sock = c->rfd = c->wfd = sock;
1461 channel_max_fd = channel_find_maxfd();
1464 /* Exhausted all addresses */
1465 error("connect_to %.100s port %d: failed.",
1466 c->connect_ctx.host, c->connect_ctx.port);
1467 channel_connect_ctx_free(&c->connect_ctx);
1469 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1470 packet_put_int(c->remote_id);
1471 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1472 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1473 packet_put_cstring(strerror(err));
1474 packet_put_cstring("");
1477 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1478 packet_put_int(c->remote_id);
1488 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1490 char buf[CHAN_RBUF];
1493 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1494 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1496 len = read(c->rfd, buf, sizeof(buf));
1497 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force)))
1499 #ifndef PTY_ZEROREAD
1502 if ((!c->isatty && len <= 0) ||
1503 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1505 debug2("channel %d: read<=0 rfd %d len %d",
1506 c->self, c->rfd, len);
1507 if (c->type != SSH_CHANNEL_OPEN) {
1508 debug2("channel %d: not open", c->self);
1511 } else if (compat13) {
1512 buffer_clear(&c->output);
1513 c->type = SSH_CHANNEL_INPUT_DRAINING;
1514 debug2("channel %d: input draining.", c->self);
1516 chan_read_failed(c);
1520 if (c->input_filter != NULL) {
1521 if (c->input_filter(c, buf, len) == -1) {
1522 debug2("channel %d: filter stops", c->self);
1523 chan_read_failed(c);
1525 } else if (c->datagram) {
1526 buffer_put_string(&c->input, buf, len);
1528 buffer_append(&c->input, buf, len);
1536 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1539 u_char *data = NULL, *buf;
1543 /* Send buffered output data to the socket. */
1545 FD_ISSET(c->wfd, writeset) &&
1546 buffer_len(&c->output) > 0) {
1547 if (c->output_filter != NULL) {
1548 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1549 debug2("channel %d: filter stops", c->self);
1550 if (c->type != SSH_CHANNEL_OPEN)
1553 chan_write_failed(c);
1556 } else if (c->datagram) {
1557 buf = data = buffer_get_string(&c->output, &dlen);
1559 buf = data = buffer_ptr(&c->output);
1560 dlen = buffer_len(&c->output);
1564 /* ignore truncated writes, datagrams might get lost */
1565 c->local_consumed += dlen + 4;
1566 len = write(c->wfd, buf, dlen);
1568 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1571 if (c->type != SSH_CHANNEL_OPEN)
1574 chan_write_failed(c);
1580 /* XXX: Later AIX versions can't push as much data to tty */
1581 if (compat20 && c->wfd_isatty)
1582 dlen = MIN(dlen, 8*1024);
1585 len = write(c->wfd, buf, dlen);
1586 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1589 if (c->type != SSH_CHANNEL_OPEN) {
1590 debug2("channel %d: not open", c->self);
1593 } else if (compat13) {
1594 buffer_clear(&c->output);
1595 debug2("channel %d: input draining.", c->self);
1596 c->type = SSH_CHANNEL_INPUT_DRAINING;
1598 chan_write_failed(c);
1602 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1603 if (tcgetattr(c->wfd, &tio) == 0 &&
1604 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1606 * Simulate echo to reduce the impact of
1607 * traffic analysis. We need to match the
1608 * size of a SSH2_MSG_CHANNEL_DATA message
1609 * (4 byte channel id + buf)
1611 packet_send_ignore(4 + len);
1615 buffer_consume(&c->output, len);
1616 if (compat20 && len > 0) {
1617 c->local_consumed += len;
1624 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1626 char buf[CHAN_RBUF];
1629 /** XXX handle drain efd, too */
1631 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1632 FD_ISSET(c->efd, writeset) &&
1633 buffer_len(&c->extended) > 0) {
1634 len = write(c->efd, buffer_ptr(&c->extended),
1635 buffer_len(&c->extended));
1636 debug2("channel %d: written %d to efd %d",
1637 c->self, len, c->efd);
1638 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1641 debug2("channel %d: closing write-efd %d",
1643 channel_close_fd(&c->efd);
1645 buffer_consume(&c->extended, len);
1646 c->local_consumed += len;
1648 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1649 (c->detach_close || FD_ISSET(c->efd, readset))) {
1650 len = read(c->efd, buf, sizeof(buf));
1651 debug2("channel %d: read %d from efd %d",
1652 c->self, len, c->efd);
1653 if (len < 0 && (errno == EINTR ||
1654 (errno == EAGAIN && !c->detach_close)))
1657 debug2("channel %d: closing read-efd %d",
1659 channel_close_fd(&c->efd);
1661 buffer_append(&c->extended, buf, len);
1670 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1675 /* Monitor control fd to detect if the slave client exits */
1676 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1677 len = read(c->ctl_fd, buf, sizeof(buf));
1678 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1681 debug2("channel %d: ctl read<=0", c->self);
1682 if (c->type != SSH_CHANNEL_OPEN) {
1683 debug2("channel %d: not open", c->self);
1687 chan_read_failed(c);
1688 chan_write_failed(c);
1692 fatal("%s: unexpected data on ctl fd", __func__);
1698 channel_check_window(Channel *c)
1700 if (c->type == SSH_CHANNEL_OPEN &&
1701 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1702 ((c->local_window_max - c->local_window >
1703 c->local_maxpacket*3) ||
1704 c->local_window < c->local_window_max/2) &&
1705 c->local_consumed > 0) {
1706 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1707 packet_put_int(c->remote_id);
1708 packet_put_int(c->local_consumed);
1710 debug2("channel %d: window %d sent adjust %d",
1711 c->self, c->local_window,
1713 c->local_window += c->local_consumed;
1714 c->local_consumed = 0;
1720 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1724 channel_handle_rfd(c, readset, writeset);
1725 channel_handle_wfd(c, readset, writeset);
1728 channel_handle_efd(c, readset, writeset);
1729 channel_handle_ctl(c, readset, writeset);
1730 channel_check_window(c);
1735 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1739 /* Send buffered output data to the socket. */
1740 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1741 len = write(c->sock, buffer_ptr(&c->output),
1742 buffer_len(&c->output));
1744 buffer_clear(&c->output);
1746 buffer_consume(&c->output, len);
1751 channel_handler_init_20(void)
1753 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1754 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1755 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1756 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1757 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1758 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1759 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1760 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1762 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1763 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1764 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1765 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1766 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1767 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1768 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1772 channel_handler_init_13(void)
1774 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1775 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1776 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1777 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1778 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1779 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1780 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1781 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1782 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1784 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1785 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1786 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1787 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1788 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1789 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1790 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1794 channel_handler_init_15(void)
1796 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1797 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1798 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1799 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1800 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1801 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1802 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1804 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1805 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1806 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1807 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1808 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1809 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1813 channel_handler_init(void)
1817 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1818 channel_pre[i] = NULL;
1819 channel_post[i] = NULL;
1822 channel_handler_init_20();
1824 channel_handler_init_13();
1826 channel_handler_init_15();
1829 /* gc dead channels */
1831 channel_garbage_collect(Channel *c)
1835 if (c->detach_user != NULL) {
1836 if (!chan_is_dead(c, c->detach_close))
1838 debug2("channel %d: gc: notify user", c->self);
1839 c->detach_user(c->self, NULL);
1840 /* if we still have a callback */
1841 if (c->detach_user != NULL)
1843 debug2("channel %d: gc: user detached", c->self);
1845 if (!chan_is_dead(c, 1))
1847 debug2("channel %d: garbage collecting", c->self);
1852 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1854 static int did_init = 0;
1859 channel_handler_init();
1862 for (i = 0; i < channels_alloc; i++) {
1866 if (ftab[c->type] != NULL)
1867 (*ftab[c->type])(c, readset, writeset);
1868 channel_garbage_collect(c);
1873 * Allocate/update select bitmasks and add any bits relevant to channels in
1877 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1878 u_int *nallocp, int rekeying)
1880 u_int n, sz, nfdset;
1882 n = MAX(*maxfdp, channel_max_fd);
1884 nfdset = howmany(n+1, NFDBITS);
1885 /* Explicitly test here, because xrealloc isn't always called */
1886 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1887 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1888 sz = nfdset * sizeof(fd_mask);
1890 /* perhaps check sz < nalloc/2 and shrink? */
1891 if (*readsetp == NULL || sz > *nallocp) {
1892 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1893 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1897 memset(*readsetp, 0, sz);
1898 memset(*writesetp, 0, sz);
1901 channel_handler(channel_pre, *readsetp, *writesetp);
1905 * After select, perform any appropriate operations for channels which have
1909 channel_after_select(fd_set *readset, fd_set *writeset)
1911 channel_handler(channel_post, readset, writeset);
1915 /* If there is data to send to the connection, enqueue some of it now. */
1917 channel_output_poll(void)
1922 for (i = 0; i < channels_alloc; i++) {
1928 * We are only interested in channels that can have buffered
1932 if (c->type != SSH_CHANNEL_OPEN &&
1933 c->type != SSH_CHANNEL_INPUT_DRAINING)
1936 if (c->type != SSH_CHANNEL_OPEN)
1940 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1941 /* XXX is this true? */
1942 debug3("channel %d: will not send data after close", c->self);
1946 /* Get the amount of buffered data for this channel. */
1947 if ((c->istate == CHAN_INPUT_OPEN ||
1948 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1949 (len = buffer_len(&c->input)) > 0) {
1955 data = buffer_get_string(&c->input,
1957 packet_start(SSH2_MSG_CHANNEL_DATA);
1958 packet_put_int(c->remote_id);
1959 packet_put_string(data, dlen);
1961 c->remote_window -= dlen + 4;
1967 * Send some data for the other side over the secure
1971 if (len > c->remote_window)
1972 len = c->remote_window;
1973 if (len > c->remote_maxpacket)
1974 len = c->remote_maxpacket;
1976 if (packet_is_interactive()) {
1980 /* Keep the packets at reasonable size. */
1981 if (len > packet_get_maxsize()/2)
1982 len = packet_get_maxsize()/2;
1986 packet_start(compat20 ?
1987 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1988 packet_put_int(c->remote_id);
1989 packet_put_string(buffer_ptr(&c->input), len);
1991 buffer_consume(&c->input, len);
1992 c->remote_window -= len;
1994 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1996 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1998 * input-buffer is empty and read-socket shutdown:
1999 * tell peer, that we will not send more data: send IEOF.
2000 * hack for extended data: delay EOF if EFD still in use.
2002 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2003 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2004 c->self, c->efd, buffer_len(&c->extended));
2008 /* Send extended data, i.e. stderr */
2010 !(c->flags & CHAN_EOF_SENT) &&
2011 c->remote_window > 0 &&
2012 (len = buffer_len(&c->extended)) > 0 &&
2013 c->extended_usage == CHAN_EXTENDED_READ) {
2014 debug2("channel %d: rwin %u elen %u euse %d",
2015 c->self, c->remote_window, buffer_len(&c->extended),
2017 if (len > c->remote_window)
2018 len = c->remote_window;
2019 if (len > c->remote_maxpacket)
2020 len = c->remote_maxpacket;
2021 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2022 packet_put_int(c->remote_id);
2023 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2024 packet_put_string(buffer_ptr(&c->extended), len);
2026 buffer_consume(&c->extended, len);
2027 c->remote_window -= len;
2028 debug2("channel %d: sent ext data %d", c->self, len);
2034 /* -- protocol input */
2038 channel_input_data(int type, u_int32_t seq, void *ctxt)
2045 /* Get the channel number and verify it. */
2046 id = packet_get_int();
2047 c = channel_lookup(id);
2049 packet_disconnect("Received data for nonexistent channel %d.", id);
2051 /* Ignore any data for non-open channels (might happen on close) */
2052 if (c->type != SSH_CHANNEL_OPEN &&
2053 c->type != SSH_CHANNEL_X11_OPEN)
2057 data = packet_get_string_ptr(&data_len);
2060 * Ignore data for protocol > 1.3 if output end is no longer open.
2061 * For protocol 2 the sending side is reducing its window as it sends
2062 * data, so we must 'fake' consumption of the data in order to ensure
2063 * that window updates are sent back. Otherwise the connection might
2066 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2068 c->local_window -= data_len;
2069 c->local_consumed += data_len;
2075 if (data_len > c->local_maxpacket) {
2076 logit("channel %d: rcvd big packet %d, maxpack %d",
2077 c->self, data_len, c->local_maxpacket);
2079 if (data_len > c->local_window) {
2080 logit("channel %d: rcvd too much data %d, win %d",
2081 c->self, data_len, c->local_window);
2084 c->local_window -= data_len;
2087 buffer_put_string(&c->output, data, data_len);
2089 buffer_append(&c->output, data, data_len);
2095 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2099 u_int data_len, tcode;
2102 /* Get the channel number and verify it. */
2103 id = packet_get_int();
2104 c = channel_lookup(id);
2107 packet_disconnect("Received extended_data for bad channel %d.", id);
2108 if (c->type != SSH_CHANNEL_OPEN) {
2109 logit("channel %d: ext data for non open", id);
2112 if (c->flags & CHAN_EOF_RCVD) {
2113 if (datafellows & SSH_BUG_EXTEOF)
2114 debug("channel %d: accepting ext data after eof", id);
2116 packet_disconnect("Received extended_data after EOF "
2117 "on channel %d.", id);
2119 tcode = packet_get_int();
2121 c->extended_usage != CHAN_EXTENDED_WRITE ||
2122 tcode != SSH2_EXTENDED_DATA_STDERR) {
2123 logit("channel %d: bad ext data", c->self);
2126 data = packet_get_string(&data_len);
2128 if (data_len > c->local_window) {
2129 logit("channel %d: rcvd too much extended_data %d, win %d",
2130 c->self, data_len, c->local_window);
2134 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2135 c->local_window -= data_len;
2136 buffer_append(&c->extended, data, data_len);
2142 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2147 id = packet_get_int();
2149 c = channel_lookup(id);
2151 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2154 /* XXX force input close */
2155 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2156 debug("channel %d: FORCE input drain", c->self);
2157 c->istate = CHAN_INPUT_WAIT_DRAIN;
2158 if (buffer_len(&c->input) == 0)
2166 channel_input_close(int type, u_int32_t seq, void *ctxt)
2171 id = packet_get_int();
2173 c = channel_lookup(id);
2175 packet_disconnect("Received close for nonexistent channel %d.", id);
2178 * Send a confirmation that we have closed the channel and no more
2179 * data is coming for it.
2181 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2182 packet_put_int(c->remote_id);
2186 * If the channel is in closed state, we have sent a close request,
2187 * and the other side will eventually respond with a confirmation.
2188 * Thus, we cannot free the channel here, because then there would be
2189 * no-one to receive the confirmation. The channel gets freed when
2190 * the confirmation arrives.
2192 if (c->type != SSH_CHANNEL_CLOSED) {
2194 * Not a closed channel - mark it as draining, which will
2195 * cause it to be freed later.
2197 buffer_clear(&c->input);
2198 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2202 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2205 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2207 int id = packet_get_int();
2208 Channel *c = channel_lookup(id);
2212 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2213 chan_rcvd_oclose(c);
2218 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2220 int id = packet_get_int();
2221 Channel *c = channel_lookup(id);
2225 packet_disconnect("Received close confirmation for "
2226 "out-of-range channel %d.", id);
2227 if (c->type != SSH_CHANNEL_CLOSED)
2228 packet_disconnect("Received close confirmation for "
2229 "non-closed channel %d (type %d).", id, c->type);
2235 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2240 id = packet_get_int();
2241 c = channel_lookup(id);
2243 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2244 packet_disconnect("Received open confirmation for "
2245 "non-opening channel %d.", id);
2246 remote_id = packet_get_int();
2247 /* Record the remote channel number and mark that the channel is now open. */
2248 c->remote_id = remote_id;
2249 c->type = SSH_CHANNEL_OPEN;
2252 c->remote_window = packet_get_int();
2253 c->remote_maxpacket = packet_get_int();
2254 if (c->open_confirm) {
2255 debug2("callback start");
2256 c->open_confirm(c->self, c->open_confirm_ctx);
2257 debug2("callback done");
2259 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2260 c->remote_window, c->remote_maxpacket);
2266 reason2txt(int reason)
2269 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2270 return "administratively prohibited";
2271 case SSH2_OPEN_CONNECT_FAILED:
2272 return "connect failed";
2273 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2274 return "unknown channel type";
2275 case SSH2_OPEN_RESOURCE_SHORTAGE:
2276 return "resource shortage";
2278 return "unknown reason";
2283 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2286 char *msg = NULL, *lang = NULL;
2289 id = packet_get_int();
2290 c = channel_lookup(id);
2292 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2293 packet_disconnect("Received open failure for "
2294 "non-opening channel %d.", id);
2296 reason = packet_get_int();
2297 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2298 msg = packet_get_string(NULL);
2299 lang = packet_get_string(NULL);
2301 logit("channel %d: open failed: %s%s%s", id,
2302 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2309 /* Free the channel. This will also close the socket. */
2315 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2324 /* Get the channel number and verify it. */
2325 id = packet_get_int();
2326 c = channel_lookup(id);
2329 logit("Received window adjust for non-open channel %d.", id);
2332 adjust = packet_get_int();
2334 debug2("channel %d: rcvd adjust %u", id, adjust);
2335 c->remote_window += adjust;
2340 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2344 char *host, *originator_string;
2347 remote_id = packet_get_int();
2348 host = packet_get_string(NULL);
2349 host_port = packet_get_int();
2351 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2352 originator_string = packet_get_string(NULL);
2354 originator_string = xstrdup("unknown (remote did not supply name)");
2357 c = channel_connect_to(host, host_port,
2358 "connected socket", originator_string);
2359 xfree(originator_string);
2362 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2363 packet_put_int(remote_id);
2366 c->remote_id = remote_id;
2371 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2374 struct channel_confirm *cc;
2377 /* Reset keepalive timeout */
2378 keep_alive_timeouts = 0;
2380 remote_id = packet_get_int();
2383 debug2("channel_input_confirm: type %d id %d", type, remote_id);
2385 if ((c = channel_lookup(remote_id)) == NULL) {
2386 logit("channel_input_success_failure: %d: unknown", remote_id);
2390 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2392 cc->cb(type, c, cc->ctx);
2393 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2394 bzero(cc, sizeof(*cc));
2398 /* -- tcp forwarding */
2401 channel_set_af(int af)
2407 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2408 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2411 int sock, r, success = 0, wildcard = 0, is_client;
2412 struct addrinfo hints, *ai, *aitop;
2413 const char *host, *addr;
2414 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2416 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2417 listen_addr : host_to_connect;
2418 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2421 error("No forward host name.");
2424 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2425 error("Forward host name too long.");
2430 * Determine whether or not a port forward listens to loopback,
2431 * specified address or wildcard. On the client, a specified bind
2432 * address will always override gateway_ports. On the server, a
2433 * gateway_ports of 1 (``yes'') will override the client's
2434 * specification and force a wildcard bind, whereas a value of 2
2435 * (``clientspecified'') will bind to whatever address the client
2438 * Special-case listen_addrs are:
2440 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2441 * "" (empty string), "*" -> wildcard v4/v6
2442 * "localhost" -> loopback v4/v6
2445 if (listen_addr == NULL) {
2446 /* No address specified: default to gateway_ports setting */
2449 } else if (gateway_ports || is_client) {
2450 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2451 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2452 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2453 (!is_client && gateway_ports == 1))
2455 else if (strcmp(listen_addr, "localhost") != 0)
2459 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2460 type, wildcard, (addr == NULL) ? "NULL" : addr);
2463 * getaddrinfo returns a loopback address if the hostname is
2464 * set to NULL and hints.ai_flags is not AI_PASSIVE
2466 memset(&hints, 0, sizeof(hints));
2467 hints.ai_family = IPv4or6;
2468 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2469 hints.ai_socktype = SOCK_STREAM;
2470 snprintf(strport, sizeof strport, "%d", listen_port);
2471 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2473 /* This really shouldn't happen */
2474 packet_disconnect("getaddrinfo: fatal error: %s",
2475 ssh_gai_strerror(r));
2477 error("channel_setup_fwd_listener: "
2478 "getaddrinfo(%.64s): %s", addr,
2479 ssh_gai_strerror(r));
2484 for (ai = aitop; ai; ai = ai->ai_next) {
2485 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2487 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2488 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2489 error("channel_setup_fwd_listener: getnameinfo failed");
2492 /* Create a port to listen for the host. */
2493 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2495 /* this is no error since kernel may not support ipv6 */
2496 verbose("socket: %.100s", strerror(errno));
2500 channel_set_reuseaddr(sock);
2502 debug("Local forwarding listening on %s port %s.", ntop, strport);
2504 /* Bind the socket to the address. */
2505 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2506 /* address can be in use ipv6 address is already bound */
2508 error("bind: %.100s", strerror(errno));
2510 verbose("bind: %.100s", strerror(errno));
2515 /* Start listening for connections on the socket. */
2516 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2517 error("listen: %.100s", strerror(errno));
2521 /* Allocate a channel number for the socket. */
2522 c = channel_new("port listener", type, sock, sock, -1,
2523 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2524 0, "port listener", 1);
2525 strlcpy(c->path, host, sizeof(c->path));
2526 c->host_port = port_to_connect;
2527 c->listening_port = listen_port;
2531 error("channel_setup_fwd_listener: cannot listen to port: %d",
2533 freeaddrinfo(aitop);
2538 channel_cancel_rport_listener(const char *host, u_short port)
2543 for (i = 0; i < channels_alloc; i++) {
2544 Channel *c = channels[i];
2546 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2547 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2548 c->listening_port == port) {
2549 debug2("%s: close channel %d", __func__, i);
2558 /* protocol local port fwd, used by ssh (and sshd in v1) */
2560 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2561 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2563 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2564 listen_host, listen_port, host_to_connect, port_to_connect,
2568 /* protocol v2 remote port fwd, used by sshd */
2570 channel_setup_remote_fwd_listener(const char *listen_address,
2571 u_short listen_port, int gateway_ports)
2573 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2574 listen_address, listen_port, NULL, 0, gateway_ports);
2578 * Initiate forwarding of connections to port "port" on remote host through
2579 * the secure channel to host:port from local side.
2583 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2584 const char *host_to_connect, u_short port_to_connect)
2586 int type, success = 0;
2588 /* Record locally that connection to this host/port is permitted. */
2589 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2590 fatal("channel_request_remote_forwarding: too many forwards");
2592 /* Send the forward request to the remote side. */
2594 const char *address_to_bind;
2595 if (listen_host == NULL) {
2596 if (datafellows & SSH_BUG_RFWD_ADDR)
2597 address_to_bind = "127.0.0.1";
2599 address_to_bind = "localhost";
2600 } else if (*listen_host == '\0' ||
2601 strcmp(listen_host, "*") == 0) {
2602 if (datafellows & SSH_BUG_RFWD_ADDR)
2603 address_to_bind = "0.0.0.0";
2605 address_to_bind = "";
2607 address_to_bind = listen_host;
2609 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2610 packet_put_cstring("tcpip-forward");
2611 packet_put_char(1); /* boolean: want reply */
2612 packet_put_cstring(address_to_bind);
2613 packet_put_int(listen_port);
2615 packet_write_wait();
2616 /* Assume that server accepts the request */
2619 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2620 packet_put_int(listen_port);
2621 packet_put_cstring(host_to_connect);
2622 packet_put_int(port_to_connect);
2624 packet_write_wait();
2626 /* Wait for response from the remote side. */
2627 type = packet_read();
2629 case SSH_SMSG_SUCCESS:
2632 case SSH_SMSG_FAILURE:
2635 /* Unknown packet */
2636 packet_disconnect("Protocol error for port forward request:"
2637 "received packet type %d.", type);
2641 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2642 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2643 permitted_opens[num_permitted_opens].listen_port = listen_port;
2644 num_permitted_opens++;
2646 return (success ? 0 : -1);
2650 * Request cancellation of remote forwarding of connection host:port from
2654 channel_request_rforward_cancel(const char *host, u_short port)
2661 for (i = 0; i < num_permitted_opens; i++) {
2662 if (permitted_opens[i].host_to_connect != NULL &&
2663 permitted_opens[i].listen_port == port)
2666 if (i >= num_permitted_opens) {
2667 debug("%s: requested forward not found", __func__);
2670 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2671 packet_put_cstring("cancel-tcpip-forward");
2673 packet_put_cstring(host == NULL ? "" : host);
2674 packet_put_int(port);
2677 permitted_opens[i].listen_port = 0;
2678 permitted_opens[i].port_to_connect = 0;
2679 xfree(permitted_opens[i].host_to_connect);
2680 permitted_opens[i].host_to_connect = NULL;
2684 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2685 * listening for the port, and sends back a success reply (or disconnect
2686 * message if there was an error).
2689 channel_input_port_forward_request(int is_root, int gateway_ports)
2691 u_short port, host_port;
2695 /* Get arguments from the packet. */
2696 port = packet_get_int();
2697 hostname = packet_get_string(NULL);
2698 host_port = packet_get_int();
2702 * Check that an unprivileged user is not trying to forward a
2705 if (port < IPPORT_RESERVED && !is_root)
2707 "Requested forwarding of port %d but user is not root.",
2710 packet_disconnect("Dynamic forwarding denied.");
2713 /* Initiate forwarding */
2714 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2715 host_port, gateway_ports);
2717 /* Free the argument string. */
2720 return (success ? 0 : -1);
2724 * Permits opening to any host/port if permitted_opens[] is empty. This is
2725 * usually called by the server, because the user could connect to any port
2726 * anyway, and the server has no way to know but to trust the client anyway.
2729 channel_permit_all_opens(void)
2731 if (num_permitted_opens == 0)
2732 all_opens_permitted = 1;
2736 channel_add_permitted_opens(char *host, int port)
2738 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2739 fatal("channel_add_permitted_opens: too many forwards");
2740 debug("allow port forwarding to host %s port %d", host, port);
2742 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2743 permitted_opens[num_permitted_opens].port_to_connect = port;
2744 num_permitted_opens++;
2746 all_opens_permitted = 0;
2750 channel_add_adm_permitted_opens(char *host, int port)
2752 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2753 fatal("channel_add_adm_permitted_opens: too many forwards");
2754 debug("config allows port forwarding to host %s port %d", host, port);
2756 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2758 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2759 return ++num_adm_permitted_opens;
2763 channel_clear_permitted_opens(void)
2767 for (i = 0; i < num_permitted_opens; i++)
2768 if (permitted_opens[i].host_to_connect != NULL)
2769 xfree(permitted_opens[i].host_to_connect);
2770 num_permitted_opens = 0;
2774 channel_clear_adm_permitted_opens(void)
2778 for (i = 0; i < num_adm_permitted_opens; i++)
2779 if (permitted_adm_opens[i].host_to_connect != NULL)
2780 xfree(permitted_adm_opens[i].host_to_connect);
2781 num_adm_permitted_opens = 0;
2785 channel_print_adm_permitted_opens(void)
2789 for (i = 0; i < num_adm_permitted_opens; i++)
2790 if (permitted_adm_opens[i].host_to_connect != NULL)
2791 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2792 permitted_adm_opens[i].port_to_connect);
2795 /* Try to start non-blocking connect to next host in cctx list */
2797 connect_next(struct channel_connect *cctx)
2799 int sock, saved_errno;
2800 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2802 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2803 if (cctx->ai->ai_family != AF_INET &&
2804 cctx->ai->ai_family != AF_INET6)
2806 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2807 ntop, sizeof(ntop), strport, sizeof(strport),
2808 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2809 error("connect_next: getnameinfo failed");
2812 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
2813 cctx->ai->ai_protocol)) == -1) {
2814 if (cctx->ai->ai_next == NULL)
2815 error("socket: %.100s", strerror(errno));
2817 verbose("socket: %.100s", strerror(errno));
2820 if (set_nonblock(sock) == -1)
2821 fatal("%s: set_nonblock(%d)", __func__, sock);
2822 if (connect(sock, cctx->ai->ai_addr,
2823 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2824 debug("connect_next: host %.100s ([%.100s]:%s): "
2825 "%.100s", cctx->host, ntop, strport,
2827 saved_errno = errno;
2829 errno = saved_errno;
2830 continue; /* fail -- try next */
2832 debug("connect_next: host %.100s ([%.100s]:%s) "
2833 "in progress, fd=%d", cctx->host, ntop, strport, sock);
2834 cctx->ai = cctx->ai->ai_next;
2842 channel_connect_ctx_free(struct channel_connect *cctx)
2846 freeaddrinfo(cctx->aitop);
2847 bzero(cctx, sizeof(*cctx));
2849 cctx->ai = cctx->aitop = NULL;
2852 /* Return CONNECTING channel to remote host, port */
2854 connect_to(const char *host, u_short port, char *ctype, char *rname)
2856 struct addrinfo hints;
2859 char strport[NI_MAXSERV];
2860 struct channel_connect cctx;
2863 memset(&hints, 0, sizeof(hints));
2864 hints.ai_family = IPv4or6;
2865 hints.ai_socktype = SOCK_STREAM;
2866 snprintf(strport, sizeof strport, "%d", port);
2867 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
2868 error("connect_to %.100s: unknown host (%s)", host,
2869 ssh_gai_strerror(gaierr));
2873 cctx.host = xstrdup(host);
2875 cctx.ai = cctx.aitop;
2877 if ((sock = connect_next(&cctx)) == -1) {
2878 error("connect to %.100s port %d failed: %s",
2879 host, port, strerror(errno));
2880 channel_connect_ctx_free(&cctx);
2883 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
2884 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
2885 c->connect_ctx = cctx;
2890 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
2894 for (i = 0; i < num_permitted_opens; i++) {
2895 if (permitted_opens[i].host_to_connect != NULL &&
2896 permitted_opens[i].listen_port == listen_port) {
2898 permitted_opens[i].host_to_connect,
2899 permitted_opens[i].port_to_connect, ctype, rname);
2902 error("WARNING: Server requests forwarding for unknown listen_port %d",
2907 /* Check if connecting to that port is permitted and connect. */
2909 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
2911 int i, permit, permit_adm = 1;
2913 permit = all_opens_permitted;
2915 for (i = 0; i < num_permitted_opens; i++)
2916 if (permitted_opens[i].host_to_connect != NULL &&
2917 permitted_opens[i].port_to_connect == port &&
2918 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2922 if (num_adm_permitted_opens > 0) {
2924 for (i = 0; i < num_adm_permitted_opens; i++)
2925 if (permitted_adm_opens[i].host_to_connect != NULL &&
2926 permitted_adm_opens[i].port_to_connect == port &&
2927 strcmp(permitted_adm_opens[i].host_to_connect, host)
2932 if (!permit || !permit_adm) {
2933 logit("Received request to connect to host %.100s port %d, "
2934 "but the request was denied.", host, port);
2937 return connect_to(host, port, ctype, rname);
2941 channel_send_window_changes(void)
2946 for (i = 0; i < channels_alloc; i++) {
2947 if (channels[i] == NULL || !channels[i]->client_tty ||
2948 channels[i]->type != SSH_CHANNEL_OPEN)
2950 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2952 channel_request_start(i, "window-change", 0);
2953 packet_put_int((u_int)ws.ws_col);
2954 packet_put_int((u_int)ws.ws_row);
2955 packet_put_int((u_int)ws.ws_xpixel);
2956 packet_put_int((u_int)ws.ws_ypixel);
2961 /* -- X11 forwarding */
2964 * Creates an internet domain socket for listening for X11 connections.
2965 * Returns 0 and a suitable display number for the DISPLAY variable
2966 * stored in display_numberp , or -1 if an error occurs.
2969 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2970 int single_connection, u_int *display_numberp, int **chanids)
2973 int display_number, sock;
2975 struct addrinfo hints, *ai, *aitop;
2976 char strport[NI_MAXSERV];
2977 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2979 if (chanids == NULL)
2982 for (display_number = x11_display_offset;
2983 display_number < MAX_DISPLAYS;
2985 port = 6000 + display_number;
2986 memset(&hints, 0, sizeof(hints));
2987 hints.ai_family = IPv4or6;
2988 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2989 hints.ai_socktype = SOCK_STREAM;
2990 snprintf(strport, sizeof strport, "%d", port);
2991 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2992 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
2995 for (ai = aitop; ai; ai = ai->ai_next) {
2996 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2998 sock = socket(ai->ai_family, ai->ai_socktype,
3001 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
3002 error("socket: %.100s", strerror(errno));
3003 freeaddrinfo(aitop);
3006 debug("x11_create_display_inet: Socket family %d not supported",
3012 if (ai->ai_family == AF_INET6) {
3014 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
3015 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
3018 if (x11_use_localhost)
3019 channel_set_reuseaddr(sock);
3020 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3021 debug2("bind port %d: %.100s", port, strerror(errno));
3024 for (n = 0; n < num_socks; n++) {
3030 socks[num_socks++] = sock;
3031 if (num_socks == NUM_SOCKS)
3034 freeaddrinfo(aitop);
3038 if (display_number >= MAX_DISPLAYS) {
3039 error("Failed to allocate internet-domain X11 display socket.");
3042 /* Start listening for connections on the socket. */
3043 for (n = 0; n < num_socks; n++) {
3045 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3046 error("listen: %.100s", strerror(errno));
3052 /* Allocate a channel for each socket. */
3053 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3054 for (n = 0; n < num_socks; n++) {
3056 nc = channel_new("x11 listener",
3057 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3058 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3059 0, "X11 inet listener", 1);
3060 nc->single_connection = single_connection;
3061 (*chanids)[n] = nc->self;
3065 /* Return the display number for the DISPLAY environment variable. */
3066 *display_numberp = display_number;
3071 connect_local_xsocket(u_int dnr)
3074 struct sockaddr_un addr;
3076 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3078 error("socket: %.100s", strerror(errno));
3079 memset(&addr, 0, sizeof(addr));
3080 addr.sun_family = AF_UNIX;
3081 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
3082 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3085 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3090 x11_connect_display(void)
3092 u_int display_number;
3093 const char *display;
3094 char buf[1024], *cp;
3095 struct addrinfo hints, *ai, *aitop;
3096 char strport[NI_MAXSERV];
3097 int gaierr, sock = 0;
3099 /* Try to open a socket for the local X server. */
3100 display = getenv("DISPLAY");
3102 error("DISPLAY not set.");
3106 * Now we decode the value of the DISPLAY variable and make a
3107 * connection to the real X server.
3111 * Check if it is a unix domain socket. Unix domain displays are in
3112 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3114 if (strncmp(display, "unix:", 5) == 0 ||
3115 display[0] == ':') {
3116 /* Connect to the unix domain socket. */
3117 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3118 error("Could not parse display number from DISPLAY: %.100s",
3122 /* Create a socket. */
3123 sock = connect_local_xsocket(display_number);
3127 /* OK, we now have a connection to the display. */
3131 * Connect to an inet socket. The DISPLAY value is supposedly
3132 * hostname:d[.s], where hostname may also be numeric IP address.
3134 strlcpy(buf, display, sizeof(buf));
3135 cp = strchr(buf, ':');
3137 error("Could not find ':' in DISPLAY: %.100s", display);
3141 /* buf now contains the host name. But first we parse the display number. */
3142 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3143 error("Could not parse display number from DISPLAY: %.100s",
3148 /* Look up the host address */
3149 memset(&hints, 0, sizeof(hints));
3150 hints.ai_family = IPv4or6;
3151 hints.ai_socktype = SOCK_STREAM;
3152 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3153 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3154 error("%.100s: unknown host. (%s)", buf,
3155 ssh_gai_strerror(gaierr));
3158 for (ai = aitop; ai; ai = ai->ai_next) {
3159 /* Create a socket. */
3160 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3162 debug2("socket: %.100s", strerror(errno));
3165 /* Connect it to the display. */
3166 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3167 debug2("connect %.100s port %u: %.100s", buf,
3168 6000 + display_number, strerror(errno));
3175 freeaddrinfo(aitop);
3177 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3186 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3187 * the remote channel number. We should do whatever we want, and respond
3188 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3193 x11_input_open(int type, u_int32_t seq, void *ctxt)
3196 int remote_id, sock = 0;
3199 debug("Received X11 open request.");
3201 remote_id = packet_get_int();
3203 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3204 remote_host = packet_get_string(NULL);
3206 remote_host = xstrdup("unknown (remote did not supply name)");
3210 /* Obtain a connection to the real X display. */
3211 sock = x11_connect_display();
3213 /* Allocate a channel for this connection. */
3214 c = channel_new("connected x11 socket",
3215 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3217 c->remote_id = remote_id;
3222 /* Send refusal to the remote host. */
3223 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3224 packet_put_int(remote_id);
3226 /* Send a confirmation to the remote host. */
3227 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3228 packet_put_int(remote_id);
3229 packet_put_int(c->self);
3234 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3237 deny_input_open(int type, u_int32_t seq, void *ctxt)
3239 int rchan = packet_get_int();
3242 case SSH_SMSG_AGENT_OPEN:
3243 error("Warning: ssh server tried agent forwarding.");
3245 case SSH_SMSG_X11_OPEN:
3246 error("Warning: ssh server tried X11 forwarding.");
3249 error("deny_input_open: type %d", type);
3252 error("Warning: this is probably a break-in attempt by a malicious server.");
3253 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3254 packet_put_int(rchan);
3259 * Requests forwarding of X11 connections, generates fake authentication
3260 * data, and enables authentication spoofing.
3261 * This should be called in the client only.
3264 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3265 const char *proto, const char *data)
3267 u_int data_len = (u_int) strlen(data) / 2;
3274 if (x11_saved_display == NULL)
3275 x11_saved_display = xstrdup(disp);
3276 else if (strcmp(disp, x11_saved_display) != 0) {
3277 error("x11_request_forwarding_with_spoofing: different "
3278 "$DISPLAY already forwarded");
3282 cp = strchr(disp, ':');
3284 cp = strchr(cp, '.');
3286 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3290 if (x11_saved_proto == NULL) {
3291 /* Save protocol name. */
3292 x11_saved_proto = xstrdup(proto);
3294 * Extract real authentication data and generate fake data
3295 * of the same length.
3297 x11_saved_data = xmalloc(data_len);
3298 x11_fake_data = xmalloc(data_len);
3299 for (i = 0; i < data_len; i++) {
3300 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3301 fatal("x11_request_forwarding: bad "
3302 "authentication data: %.100s", data);
3305 x11_saved_data[i] = value;
3306 x11_fake_data[i] = rnd & 0xff;
3309 x11_saved_data_len = data_len;
3310 x11_fake_data_len = data_len;
3313 /* Convert the fake data into hex. */
3314 new_data = tohex(x11_fake_data, data_len);
3316 /* Send the request packet. */
3318 channel_request_start(client_session_id, "x11-req", 0);
3319 packet_put_char(0); /* XXX bool single connection */
3321 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3323 packet_put_cstring(proto);
3324 packet_put_cstring(new_data);
3325 packet_put_int(screen_number);
3327 packet_write_wait();
3332 /* -- agent forwarding */
3334 /* Sends a message to the server to request authentication fd forwarding. */
3337 auth_request_forwarding(void)
3339 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3341 packet_write_wait();