blob: 090cbf095328280d97540edf27d0e536a114f6ef [file] [log] [blame]
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 *
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 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100017
18#include "includes.h"
Damien Miller7bcb0892000-03-11 20:45:40 +110019RCSID("$Id: channels.c,v 1.18 2000/03/11 09:45:41 damien Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100020
21#include "ssh.h"
22#include "packet.h"
23#include "xmalloc.h"
24#include "buffer.h"
25#include "authfd.h"
26#include "uidswap.h"
Damien Miller6d7b2cd1999-11-12 15:19:27 +110027#include "readconf.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100028#include "servconf.h"
29
30#include "channels.h"
31#include "nchan.h"
32#include "compat.h"
33
34/* Maximum number of fake X11 displays to try. */
35#define MAX_DISPLAYS 1000
36
37/* Max len of agent socket */
38#define MAX_SOCKET_NAME 100
39
Damien Miller5428f641999-11-25 11:54:57 +110040/*
41 * Pointer to an array containing all allocated channels. The array is
42 * dynamically extended as needed.
43 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044static Channel *channels = NULL;
45
Damien Miller5428f641999-11-25 11:54:57 +110046/*
47 * Size of the channel array. All slots of the array must always be
48 * initialized (at least the type field); unused slots are marked with type
49 * SSH_CHANNEL_FREE.
50 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100051static int channels_alloc = 0;
52
Damien Miller5428f641999-11-25 11:54:57 +110053/*
54 * Maximum file descriptor value used in any of the channels. This is
55 * updated in channel_allocate.
56 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100057static int channel_max_fd_value = 0;
58
59/* Name and directory of socket for authentication agent forwarding. */
60static char *channel_forwarded_auth_socket_name = NULL;
Damien Miller95def091999-11-25 00:26:21 +110061static char *channel_forwarded_auth_socket_dir = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100062
63/* Saved X11 authentication protocol name. */
64char *x11_saved_proto = NULL;
65
66/* Saved X11 authentication data. This is the real data. */
67char *x11_saved_data = NULL;
68unsigned int x11_saved_data_len = 0;
69
Damien Miller5428f641999-11-25 11:54:57 +110070/*
71 * Fake X11 authentication data. This is what the server will be sending us;
72 * we should replace any occurrences of this by the real data.
73 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100074char *x11_fake_data = NULL;
75unsigned int x11_fake_data_len;
76
Damien Miller5428f641999-11-25 11:54:57 +110077/*
78 * Data structure for storing which hosts are permitted for forward requests.
79 * The local sides of any remote forwards are stored in this array to prevent
80 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
81 * network (which might be behind a firewall).
82 */
Damien Miller95def091999-11-25 00:26:21 +110083typedef struct {
84 char *host; /* Host name. */
Damien Milleraae6c611999-12-06 11:47:28 +110085 u_short port; /* Port number. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100086} ForwardPermission;
87
88/* List of all permitted host/port pairs to connect. */
89static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
90/* Number of permitted host/port pairs in the array. */
91static int num_permitted_opens = 0;
Damien Miller5428f641999-11-25 11:54:57 +110092/*
93 * If this is true, all opens are permitted. This is the case on the server
94 * on which we have to trust the client anyway, and the user could do
95 * anything after logging in anyway.
96 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100097static int all_opens_permitted = 0;
98
99/* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */
100static int have_hostname_in_open = 0;
101
102/* Sets specific protocol options. */
103
Damien Miller95def091999-11-25 00:26:21 +1100104void
105channel_set_options(int hostname_in_open)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000106{
Damien Miller95def091999-11-25 00:26:21 +1100107 have_hostname_in_open = hostname_in_open;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000108}
109
Damien Miller5428f641999-11-25 11:54:57 +1100110/*
111 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
112 * called by the server, because the user could connect to any port anyway,
113 * and the server has no way to know but to trust the client anyway.
114 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000115
Damien Miller95def091999-11-25 00:26:21 +1100116void
117channel_permit_all_opens()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000118{
Damien Miller95def091999-11-25 00:26:21 +1100119 all_opens_permitted = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000120}
121
Damien Miller5428f641999-11-25 11:54:57 +1100122/*
123 * Allocate a new channel object and set its type and socket. This will cause
124 * remote_name to be freed.
125 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000126
Damien Miller95def091999-11-25 00:26:21 +1100127int
128channel_allocate(int type, int sock, char *remote_name)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000129{
Damien Miller95def091999-11-25 00:26:21 +1100130 int i, found;
131 Channel *c;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000132
Damien Miller95def091999-11-25 00:26:21 +1100133 /* Update the maximum file descriptor value. */
134 if (sock > channel_max_fd_value)
135 channel_max_fd_value = sock;
Damien Miller5428f641999-11-25 11:54:57 +1100136 /* XXX set close-on-exec -markus */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000137
Damien Miller95def091999-11-25 00:26:21 +1100138 /* Do initial allocation if this is the first call. */
139 if (channels_alloc == 0) {
140 channels_alloc = 10;
141 channels = xmalloc(channels_alloc * sizeof(Channel));
142 for (i = 0; i < channels_alloc; i++)
143 channels[i].type = SSH_CHANNEL_FREE;
Damien Miller5428f641999-11-25 11:54:57 +1100144 /*
145 * Kludge: arrange a call to channel_stop_listening if we
146 * terminate with fatal().
147 */
Damien Miller95def091999-11-25 00:26:21 +1100148 fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
149 }
150 /* Try to find a free slot where to put the new channel. */
151 for (found = -1, i = 0; i < channels_alloc; i++)
152 if (channels[i].type == SSH_CHANNEL_FREE) {
153 /* Found a free slot. */
154 found = i;
155 break;
156 }
157 if (found == -1) {
Damien Miller5428f641999-11-25 11:54:57 +1100158 /* There are no free slots. Take last+1 slot and expand the array. */
Damien Miller95def091999-11-25 00:26:21 +1100159 found = channels_alloc;
160 channels_alloc += 10;
161 debug("channel: expanding %d", channels_alloc);
162 channels = xrealloc(channels, channels_alloc * sizeof(Channel));
163 for (i = found; i < channels_alloc; i++)
164 channels[i].type = SSH_CHANNEL_FREE;
165 }
166 /* Initialize and return new channel number. */
167 c = &channels[found];
168 buffer_init(&c->input);
169 buffer_init(&c->output);
170 chan_init_iostates(c);
171 c->self = found;
172 c->type = type;
173 c->sock = sock;
174 c->remote_id = -1;
175 c->remote_name = remote_name;
176 debug("channel %d: new [%s]", found, remote_name);
177 return found;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000178}
179
180/* Free the channel and close its socket. */
181
Damien Miller95def091999-11-25 00:26:21 +1100182void
183channel_free(int channel)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000184{
Damien Miller95def091999-11-25 00:26:21 +1100185 if (channel < 0 || channel >= channels_alloc ||
186 channels[channel].type == SSH_CHANNEL_FREE)
187 packet_disconnect("channel free: bad local channel %d", channel);
Damien Millerfd7c9111999-11-08 16:15:55 +1100188
Damien Miller95def091999-11-25 00:26:21 +1100189 if (compat13)
190 shutdown(channels[channel].sock, SHUT_RDWR);
191 close(channels[channel].sock);
192 buffer_free(&channels[channel].input);
193 buffer_free(&channels[channel].output);
194 channels[channel].type = SSH_CHANNEL_FREE;
195 if (channels[channel].remote_name) {
196 xfree(channels[channel].remote_name);
197 channels[channel].remote_name = NULL;
198 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000199}
200
Damien Miller5428f641999-11-25 11:54:57 +1100201/*
202 * This is called just before select() to add any bits relevant to channels
203 * in the select bitmasks.
204 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000205
Damien Miller95def091999-11-25 00:26:21 +1100206void
207channel_prepare_select(fd_set * readset, fd_set * writeset)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000208{
Damien Miller95def091999-11-25 00:26:21 +1100209 int i;
210 Channel *ch;
211 unsigned char *ucp;
212 unsigned int proto_len, data_len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000213
Damien Miller95def091999-11-25 00:26:21 +1100214 for (i = 0; i < channels_alloc; i++) {
215 ch = &channels[i];
216redo:
217 switch (ch->type) {
218 case SSH_CHANNEL_X11_LISTENER:
219 case SSH_CHANNEL_PORT_LISTENER:
220 case SSH_CHANNEL_AUTH_SOCKET:
221 FD_SET(ch->sock, readset);
222 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000223
Damien Miller95def091999-11-25 00:26:21 +1100224 case SSH_CHANNEL_OPEN:
225 if (compat13) {
226 if (buffer_len(&ch->input) < packet_get_maxsize())
227 FD_SET(ch->sock, readset);
228 if (buffer_len(&ch->output) > 0)
229 FD_SET(ch->sock, writeset);
230 break;
231 }
232 /* test whether sockets are 'alive' for read/write */
233 if (ch->istate == CHAN_INPUT_OPEN)
234 if (buffer_len(&ch->input) < packet_get_maxsize())
235 FD_SET(ch->sock, readset);
236 if (ch->ostate == CHAN_OUTPUT_OPEN ||
237 ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
238 if (buffer_len(&ch->output) > 0) {
239 FD_SET(ch->sock, writeset);
240 } else if (ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
241 chan_obuf_empty(ch);
242 }
243 }
244 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000245
Damien Miller95def091999-11-25 00:26:21 +1100246 case SSH_CHANNEL_INPUT_DRAINING:
247 if (!compat13)
248 fatal("cannot happen: IN_DRAIN");
249 if (buffer_len(&ch->input) == 0) {
250 packet_start(SSH_MSG_CHANNEL_CLOSE);
251 packet_put_int(ch->remote_id);
252 packet_send();
253 ch->type = SSH_CHANNEL_CLOSED;
Damien Miller68e45de1999-12-27 23:54:55 +1100254 debug("Closing channel %d after input drain.", ch->self);
Damien Miller95def091999-11-25 00:26:21 +1100255 break;
256 }
257 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000258
Damien Miller95def091999-11-25 00:26:21 +1100259 case SSH_CHANNEL_OUTPUT_DRAINING:
260 if (!compat13)
261 fatal("cannot happen: OUT_DRAIN");
262 if (buffer_len(&ch->output) == 0) {
263 channel_free(i);
264 break;
265 }
266 FD_SET(ch->sock, writeset);
267 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000268
Damien Miller95def091999-11-25 00:26:21 +1100269 case SSH_CHANNEL_X11_OPEN:
Damien Miller5428f641999-11-25 11:54:57 +1100270 /*
271 * This is a special state for X11 authentication
272 * spoofing. An opened X11 connection (when
273 * authentication spoofing is being done) remains in
274 * this state until the first packet has been
275 * completely read. The authentication data in that
276 * packet is then substituted by the real data if it
277 * matches the fake data, and the channel is put into
278 * normal mode.
279 */
Damien Miller95def091999-11-25 00:26:21 +1100280 /* Check if the fixed size part of the packet is in buffer. */
281 if (buffer_len(&ch->output) < 12)
282 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000283
Damien Miller95def091999-11-25 00:26:21 +1100284 /* Parse the lengths of variable-length fields. */
285 ucp = (unsigned char *) buffer_ptr(&ch->output);
286 if (ucp[0] == 0x42) { /* Byte order MSB first. */
287 proto_len = 256 * ucp[6] + ucp[7];
288 data_len = 256 * ucp[8] + ucp[9];
289 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
290 proto_len = ucp[6] + 256 * ucp[7];
291 data_len = ucp[8] + 256 * ucp[9];
292 } else {
293 debug("Initial X11 packet contains bad byte order byte: 0x%x",
294 ucp[0]);
295 ch->type = SSH_CHANNEL_OPEN;
296 goto reject;
297 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000298
Damien Miller95def091999-11-25 00:26:21 +1100299 /* Check if the whole packet is in buffer. */
300 if (buffer_len(&ch->output) <
301 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
302 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000303
Damien Miller95def091999-11-25 00:26:21 +1100304 /* Check if authentication protocol matches. */
305 if (proto_len != strlen(x11_saved_proto) ||
306 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
307 debug("X11 connection uses different authentication protocol.");
308 ch->type = SSH_CHANNEL_OPEN;
309 goto reject;
310 }
311 /* Check if authentication data matches our fake data. */
312 if (data_len != x11_fake_data_len ||
313 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
314 x11_fake_data, x11_fake_data_len) != 0) {
315 debug("X11 auth data does not match fake data.");
316 ch->type = SSH_CHANNEL_OPEN;
317 goto reject;
318 }
319 /* Check fake data length */
320 if (x11_fake_data_len != x11_saved_data_len) {
321 error("X11 fake_data_len %d != saved_data_len %d",
322 x11_fake_data_len, x11_saved_data_len);
323 ch->type = SSH_CHANNEL_OPEN;
324 goto reject;
325 }
Damien Miller5428f641999-11-25 11:54:57 +1100326 /*
327 * Received authentication protocol and data match
328 * our fake data. Substitute the fake data with real
329 * data.
330 */
Damien Miller95def091999-11-25 00:26:21 +1100331 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
332 x11_saved_data, x11_saved_data_len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000333
Damien Miller95def091999-11-25 00:26:21 +1100334 /* Start normal processing for the channel. */
335 ch->type = SSH_CHANNEL_OPEN;
336 goto redo;
Damien Millerfd7c9111999-11-08 16:15:55 +1100337
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000338 reject:
Damien Miller5428f641999-11-25 11:54:57 +1100339 /*
340 * We have received an X11 connection that has bad
341 * authentication information.
342 */
Damien Miller95def091999-11-25 00:26:21 +1100343 log("X11 connection rejected because of wrong authentication.\r\n");
344 buffer_clear(&ch->input);
345 buffer_clear(&ch->output);
346 if (compat13) {
347 close(ch->sock);
348 ch->sock = -1;
349 ch->type = SSH_CHANNEL_CLOSED;
350 packet_start(SSH_MSG_CHANNEL_CLOSE);
351 packet_put_int(ch->remote_id);
352 packet_send();
353 } else {
354 debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate);
355 chan_read_failed(ch);
356 chan_write_failed(ch);
357 debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate);
358 }
359 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000360
Damien Miller95def091999-11-25 00:26:21 +1100361 case SSH_CHANNEL_FREE:
362 default:
363 continue;
364 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000365 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000366}
367
Damien Miller5428f641999-11-25 11:54:57 +1100368/*
369 * After select, perform any appropriate operations for channels which have
370 * events pending.
371 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000372
Damien Miller95def091999-11-25 00:26:21 +1100373void
374channel_after_select(fd_set * readset, fd_set * writeset)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000375{
Damien Miller95def091999-11-25 00:26:21 +1100376 struct sockaddr addr;
Damien Miller34132e52000-01-14 15:45:46 +1100377 int newsock, i, newch, len;
378 socklen_t addrlen;
Damien Miller95def091999-11-25 00:26:21 +1100379 Channel *ch;
380 char buf[16384], *remote_hostname;
381
382 /* Loop over all channels... */
383 for (i = 0; i < channels_alloc; i++) {
384 ch = &channels[i];
385 switch (ch->type) {
386 case SSH_CHANNEL_X11_LISTENER:
387 /* This is our fake X11 server socket. */
388 if (FD_ISSET(ch->sock, readset)) {
389 debug("X11 connection requested.");
390 addrlen = sizeof(addr);
391 newsock = accept(ch->sock, &addr, &addrlen);
392 if (newsock < 0) {
393 error("accept: %.100s", strerror(errno));
394 break;
395 }
396 remote_hostname = get_remote_hostname(newsock);
397 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
398 remote_hostname, get_peer_port(newsock));
399 xfree(remote_hostname);
400 newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
401 xstrdup(buf));
402 packet_start(SSH_SMSG_X11_OPEN);
403 packet_put_int(newch);
404 if (have_hostname_in_open)
405 packet_put_string(buf, strlen(buf));
406 packet_send();
407 }
408 break;
409
410 case SSH_CHANNEL_PORT_LISTENER:
Damien Miller5428f641999-11-25 11:54:57 +1100411 /*
412 * This socket is listening for connections to a
413 * forwarded TCP/IP port.
414 */
Damien Miller95def091999-11-25 00:26:21 +1100415 if (FD_ISSET(ch->sock, readset)) {
Damien Miller34132e52000-01-14 15:45:46 +1100416 debug("Connection to port %d forwarding to %.100s port %d requested.",
Damien Miller95def091999-11-25 00:26:21 +1100417 ch->listening_port, ch->path, ch->host_port);
418 addrlen = sizeof(addr);
419 newsock = accept(ch->sock, &addr, &addrlen);
420 if (newsock < 0) {
421 error("accept: %.100s", strerror(errno));
422 break;
423 }
424 remote_hostname = get_remote_hostname(newsock);
Damien Miller34132e52000-01-14 15:45:46 +1100425 snprintf(buf, sizeof buf, "listen port %d for %.100s port %d, connect from %.200s port %d",
Damien Miller95def091999-11-25 00:26:21 +1100426 ch->listening_port, ch->path, ch->host_port,
427 remote_hostname, get_peer_port(newsock));
428 xfree(remote_hostname);
429 newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
430 xstrdup(buf));
431 packet_start(SSH_MSG_PORT_OPEN);
432 packet_put_int(newch);
433 packet_put_string(ch->path, strlen(ch->path));
434 packet_put_int(ch->host_port);
435 if (have_hostname_in_open)
436 packet_put_string(buf, strlen(buf));
437 packet_send();
438 }
439 break;
440
441 case SSH_CHANNEL_AUTH_SOCKET:
Damien Miller5428f641999-11-25 11:54:57 +1100442 /*
443 * This is the authentication agent socket listening
444 * for connections from clients.
445 */
Damien Miller95def091999-11-25 00:26:21 +1100446 if (FD_ISSET(ch->sock, readset)) {
Damien Miller68e45de1999-12-27 23:54:55 +1100447 addrlen = sizeof(addr);
448 newsock = accept(ch->sock, &addr, &addrlen);
Damien Miller95def091999-11-25 00:26:21 +1100449 if (newsock < 0) {
450 error("accept from auth socket: %.100s", strerror(errno));
451 break;
452 }
Damien Miller68e45de1999-12-27 23:54:55 +1100453 newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
Damien Miller95def091999-11-25 00:26:21 +1100454 xstrdup("accepted auth socket"));
455 packet_start(SSH_SMSG_AGENT_OPEN);
Damien Miller68e45de1999-12-27 23:54:55 +1100456 packet_put_int(newch);
Damien Miller95def091999-11-25 00:26:21 +1100457 packet_send();
458 }
459 break;
460
461 case SSH_CHANNEL_OPEN:
Damien Miller5428f641999-11-25 11:54:57 +1100462 /*
463 * This is an open two-way communication channel. It
464 * is not of interest to us at this point what kind
465 * of data is being transmitted.
466 */
Damien Miller95def091999-11-25 00:26:21 +1100467
Damien Miller5428f641999-11-25 11:54:57 +1100468 /*
469 * Read available incoming data and append it to
470 * buffer; shutdown socket, if read or write failes
471 */
Damien Miller95def091999-11-25 00:26:21 +1100472 if (FD_ISSET(ch->sock, readset)) {
473 len = read(ch->sock, buf, sizeof(buf));
474 if (len <= 0) {
475 if (compat13) {
476 buffer_consume(&ch->output, buffer_len(&ch->output));
477 ch->type = SSH_CHANNEL_INPUT_DRAINING;
478 debug("Channel %d status set to input draining.", i);
479 } else {
480 chan_read_failed(ch);
481 }
482 break;
483 }
484 buffer_append(&ch->input, buf, len);
485 }
486 /* Send buffered output data to the socket. */
487 if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) {
488 len = write(ch->sock, buffer_ptr(&ch->output),
489 buffer_len(&ch->output));
490 if (len <= 0) {
491 if (compat13) {
492 buffer_consume(&ch->output, buffer_len(&ch->output));
493 debug("Channel %d status set to input draining.", i);
494 ch->type = SSH_CHANNEL_INPUT_DRAINING;
495 } else {
496 chan_write_failed(ch);
497 }
498 break;
499 }
500 buffer_consume(&ch->output, len);
501 }
502 break;
503
504 case SSH_CHANNEL_OUTPUT_DRAINING:
505 if (!compat13)
506 fatal("cannot happen: OUT_DRAIN");
507 /* Send buffered output data to the socket. */
508 if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) {
509 len = write(ch->sock, buffer_ptr(&ch->output),
510 buffer_len(&ch->output));
511 if (len <= 0)
512 buffer_consume(&ch->output, buffer_len(&ch->output));
513 else
514 buffer_consume(&ch->output, len);
515 }
516 break;
517
518 case SSH_CHANNEL_X11_OPEN:
519 case SSH_CHANNEL_FREE:
520 default:
521 continue;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000522 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000523 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000524}
525
526/* If there is data to send to the connection, send some of it now. */
527
Damien Miller95def091999-11-25 00:26:21 +1100528void
529channel_output_poll()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000530{
Damien Miller95def091999-11-25 00:26:21 +1100531 int len, i;
532 Channel *ch;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000533
Damien Miller95def091999-11-25 00:26:21 +1100534 for (i = 0; i < channels_alloc; i++) {
535 ch = &channels[i];
Damien Miller34132e52000-01-14 15:45:46 +1100536
Damien Miller5428f641999-11-25 11:54:57 +1100537 /* We are only interested in channels that can have buffered incoming data. */
Damien Miller34132e52000-01-14 15:45:46 +1100538 if (compat13) {
539 if (ch->type != SSH_CHANNEL_OPEN &&
540 ch->type != SSH_CHANNEL_INPUT_DRAINING)
541 continue;
542 } else {
543 if (ch->type != SSH_CHANNEL_OPEN)
544 continue;
545 if (ch->istate != CHAN_INPUT_OPEN &&
546 ch->istate != CHAN_INPUT_WAIT_DRAIN)
547 continue;
548 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000549
Damien Miller95def091999-11-25 00:26:21 +1100550 /* Get the amount of buffered data for this channel. */
551 len = buffer_len(&ch->input);
552 if (len > 0) {
Damien Miller5428f641999-11-25 11:54:57 +1100553 /* Send some data for the other side over the secure connection. */
Damien Miller95def091999-11-25 00:26:21 +1100554 if (packet_is_interactive()) {
555 if (len > 1024)
556 len = 512;
557 } else {
558 /* Keep the packets at reasonable size. */
Damien Miller68e45de1999-12-27 23:54:55 +1100559 if (len > packet_get_maxsize()/2)
560 len = packet_get_maxsize()/2;
Damien Miller95def091999-11-25 00:26:21 +1100561 }
562 packet_start(SSH_MSG_CHANNEL_DATA);
563 packet_put_int(ch->remote_id);
564 packet_put_string(buffer_ptr(&ch->input), len);
565 packet_send();
566 buffer_consume(&ch->input, len);
567 } else if (ch->istate == CHAN_INPUT_WAIT_DRAIN) {
568 if (compat13)
569 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
Damien Miller5428f641999-11-25 11:54:57 +1100570 /*
571 * input-buffer is empty and read-socket shutdown:
572 * tell peer, that we will not send more data: send IEOF
573 */
Damien Miller95def091999-11-25 00:26:21 +1100574 chan_ibuf_empty(ch);
575 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000576 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000577}
578
Damien Miller5428f641999-11-25 11:54:57 +1100579/*
580 * This is called when a packet of type CHANNEL_DATA has just been received.
581 * The message type has already been consumed, but channel number and data is
582 * still there.
583 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000584
Damien Miller95def091999-11-25 00:26:21 +1100585void
586channel_input_data(int payload_len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000587{
Damien Miller34132e52000-01-14 15:45:46 +1100588 int id;
Damien Miller95def091999-11-25 00:26:21 +1100589 char *data;
590 unsigned int data_len;
Damien Miller34132e52000-01-14 15:45:46 +1100591 Channel *ch;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000592
Damien Miller95def091999-11-25 00:26:21 +1100593 /* Get the channel number and verify it. */
Damien Miller34132e52000-01-14 15:45:46 +1100594 id = packet_get_int();
595 if (id < 0 || id >= channels_alloc)
596 packet_disconnect("Received data for nonexistent channel %d.", id);
597 ch = &channels[id];
598
599 if (ch->type == SSH_CHANNEL_FREE)
600 packet_disconnect("Received data for free channel %d.", ch->self);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000601
Damien Miller95def091999-11-25 00:26:21 +1100602 /* Ignore any data for non-open channels (might happen on close) */
Damien Miller34132e52000-01-14 15:45:46 +1100603 if (ch->type != SSH_CHANNEL_OPEN &&
604 ch->type != SSH_CHANNEL_X11_OPEN)
605 return;
606
607 /* same for protocol 1.5 if output end is no longer open */
608 if (!compat13 && ch->ostate != CHAN_OUTPUT_OPEN)
Damien Miller95def091999-11-25 00:26:21 +1100609 return;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000610
Damien Miller95def091999-11-25 00:26:21 +1100611 /* Get the data. */
612 data = packet_get_string(&data_len);
613 packet_integrity_check(payload_len, 4 + 4 + data_len, SSH_MSG_CHANNEL_DATA);
Damien Miller34132e52000-01-14 15:45:46 +1100614 buffer_append(&ch->output, data, data_len);
Damien Miller95def091999-11-25 00:26:21 +1100615 xfree(data);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000616}
617
Damien Miller5428f641999-11-25 11:54:57 +1100618/*
619 * Returns true if no channel has too much buffered data, and false if one or
620 * more channel is overfull.
621 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000622
Damien Miller95def091999-11-25 00:26:21 +1100623int
624channel_not_very_much_buffered_data()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000625{
Damien Miller95def091999-11-25 00:26:21 +1100626 unsigned int i;
627 Channel *ch;
628
629 for (i = 0; i < channels_alloc; i++) {
630 ch = &channels[i];
Damien Miller34132e52000-01-14 15:45:46 +1100631 if (ch->type == SSH_CHANNEL_OPEN) {
Damien Miller95def091999-11-25 00:26:21 +1100632 if (buffer_len(&ch->input) > packet_get_maxsize())
633 return 0;
634 if (buffer_len(&ch->output) > packet_get_maxsize())
635 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100636 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000637 }
Damien Miller95def091999-11-25 00:26:21 +1100638 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000639}
640
641/* This is called after receiving CHANNEL_CLOSE/IEOF. */
642
Damien Miller95def091999-11-25 00:26:21 +1100643void
644channel_input_close()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000645{
Damien Miller95def091999-11-25 00:26:21 +1100646 int channel;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000647
Damien Miller95def091999-11-25 00:26:21 +1100648 /* Get the channel number and verify it. */
649 channel = packet_get_int();
650 if (channel < 0 || channel >= channels_alloc ||
651 channels[channel].type == SSH_CHANNEL_FREE)
652 packet_disconnect("Received data for nonexistent channel %d.", channel);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000653
Damien Miller95def091999-11-25 00:26:21 +1100654 if (!compat13) {
655 /* proto version 1.5 overloads CLOSE with IEOF */
656 chan_rcvd_ieof(&channels[channel]);
657 return;
658 }
Damien Miller5428f641999-11-25 11:54:57 +1100659
660 /*
661 * Send a confirmation that we have closed the channel and no more
662 * data is coming for it.
663 */
Damien Miller95def091999-11-25 00:26:21 +1100664 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
665 packet_put_int(channels[channel].remote_id);
666 packet_send();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000667
Damien Miller5428f641999-11-25 11:54:57 +1100668 /*
669 * If the channel is in closed state, we have sent a close request,
670 * and the other side will eventually respond with a confirmation.
671 * Thus, we cannot free the channel here, because then there would be
672 * no-one to receive the confirmation. The channel gets freed when
673 * the confirmation arrives.
674 */
Damien Miller95def091999-11-25 00:26:21 +1100675 if (channels[channel].type != SSH_CHANNEL_CLOSED) {
Damien Miller5428f641999-11-25 11:54:57 +1100676 /*
677 * Not a closed channel - mark it as draining, which will
678 * cause it to be freed later.
679 */
Damien Miller95def091999-11-25 00:26:21 +1100680 buffer_consume(&channels[channel].input,
681 buffer_len(&channels[channel].input));
682 channels[channel].type = SSH_CHANNEL_OUTPUT_DRAINING;
683 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000684}
685
686/* This is called after receiving CHANNEL_CLOSE_CONFIRMATION/OCLOSE. */
687
Damien Miller95def091999-11-25 00:26:21 +1100688void
689channel_input_close_confirmation()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000690{
Damien Miller95def091999-11-25 00:26:21 +1100691 int channel;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000692
Damien Miller95def091999-11-25 00:26:21 +1100693 /* Get the channel number and verify it. */
694 channel = packet_get_int();
695 if (channel < 0 || channel >= channels_alloc)
696 packet_disconnect("Received close confirmation for out-of-range channel %d.",
697 channel);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000698
Damien Miller95def091999-11-25 00:26:21 +1100699 if (!compat13) {
700 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
701 chan_rcvd_oclose(&channels[channel]);
702 return;
703 }
704 if (channels[channel].type != SSH_CHANNEL_CLOSED)
705 packet_disconnect("Received close confirmation for non-closed channel %d (type %d).",
706 channel, channels[channel].type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000707
Damien Miller95def091999-11-25 00:26:21 +1100708 /* Free the channel. */
709 channel_free(channel);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000710}
711
712/* This is called after receiving CHANNEL_OPEN_CONFIRMATION. */
713
Damien Miller95def091999-11-25 00:26:21 +1100714void
715channel_input_open_confirmation()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000716{
Damien Miller95def091999-11-25 00:26:21 +1100717 int channel, remote_channel;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000718
Damien Miller95def091999-11-25 00:26:21 +1100719 /* Get the channel number and verify it. */
720 channel = packet_get_int();
721 if (channel < 0 || channel >= channels_alloc ||
722 channels[channel].type != SSH_CHANNEL_OPENING)
723 packet_disconnect("Received open confirmation for non-opening channel %d.",
724 channel);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000725
Damien Miller95def091999-11-25 00:26:21 +1100726 /* Get remote side's id for this channel. */
727 remote_channel = packet_get_int();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000728
Damien Miller5428f641999-11-25 11:54:57 +1100729 /* Record the remote channel number and mark that the channel is now open. */
Damien Miller95def091999-11-25 00:26:21 +1100730 channels[channel].remote_id = remote_channel;
731 channels[channel].type = SSH_CHANNEL_OPEN;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000732}
733
734/* This is called after receiving CHANNEL_OPEN_FAILURE from the other side. */
735
Damien Miller95def091999-11-25 00:26:21 +1100736void
737channel_input_open_failure()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000738{
Damien Miller95def091999-11-25 00:26:21 +1100739 int channel;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000740
Damien Miller95def091999-11-25 00:26:21 +1100741 /* Get the channel number and verify it. */
742 channel = packet_get_int();
743 if (channel < 0 || channel >= channels_alloc ||
744 channels[channel].type != SSH_CHANNEL_OPENING)
745 packet_disconnect("Received open failure for non-opening channel %d.",
746 channel);
747
748 /* Free the channel. This will also close the socket. */
749 channel_free(channel);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000750}
751
Damien Miller5428f641999-11-25 11:54:57 +1100752/*
753 * Stops listening for channels, and removes any unix domain sockets that we
754 * might have.
755 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000756
Damien Miller95def091999-11-25 00:26:21 +1100757void
758channel_stop_listening()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000759{
Damien Miller95def091999-11-25 00:26:21 +1100760 int i;
761 for (i = 0; i < channels_alloc; i++) {
762 switch (channels[i].type) {
763 case SSH_CHANNEL_AUTH_SOCKET:
764 close(channels[i].sock);
765 remove(channels[i].path);
766 channel_free(i);
767 break;
768 case SSH_CHANNEL_PORT_LISTENER:
769 case SSH_CHANNEL_X11_LISTENER:
770 close(channels[i].sock);
771 channel_free(i);
772 break;
773 default:
774 break;
775 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000776 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000777}
778
Damien Miller5428f641999-11-25 11:54:57 +1100779/*
780 * Closes the sockets of all channels. This is used to close extra file
781 * descriptors after a fork.
782 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000783
Damien Miller95def091999-11-25 00:26:21 +1100784void
785channel_close_all()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000786{
Damien Miller95def091999-11-25 00:26:21 +1100787 int i;
788 for (i = 0; i < channels_alloc; i++) {
789 if (channels[i].type != SSH_CHANNEL_FREE)
790 close(channels[i].sock);
791 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000792}
793
794/* Returns the maximum file descriptor number used by the channels. */
795
Damien Miller95def091999-11-25 00:26:21 +1100796int
797channel_max_fd()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000798{
Damien Miller95def091999-11-25 00:26:21 +1100799 return channel_max_fd_value;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000800}
801
802/* Returns true if any channel is still open. */
803
Damien Miller95def091999-11-25 00:26:21 +1100804int
805channel_still_open()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000806{
Damien Miller95def091999-11-25 00:26:21 +1100807 unsigned int i;
808 for (i = 0; i < channels_alloc; i++)
809 switch (channels[i].type) {
810 case SSH_CHANNEL_FREE:
811 case SSH_CHANNEL_X11_LISTENER:
812 case SSH_CHANNEL_PORT_LISTENER:
813 case SSH_CHANNEL_CLOSED:
814 case SSH_CHANNEL_AUTH_SOCKET:
815 continue;
816 case SSH_CHANNEL_OPENING:
817 case SSH_CHANNEL_OPEN:
818 case SSH_CHANNEL_X11_OPEN:
819 return 1;
820 case SSH_CHANNEL_INPUT_DRAINING:
821 case SSH_CHANNEL_OUTPUT_DRAINING:
822 if (!compat13)
823 fatal("cannot happen: OUT_DRAIN");
824 return 1;
825 default:
826 fatal("channel_still_open: bad channel type %d", channels[i].type);
827 /* NOTREACHED */
828 }
829 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000830}
831
Damien Miller5428f641999-11-25 11:54:57 +1100832/*
833 * Returns a message describing the currently open forwarded connections,
834 * suitable for sending to the client. The message contains crlf pairs for
835 * newlines.
836 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000837
Damien Miller95def091999-11-25 00:26:21 +1100838char *
839channel_open_message()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000840{
Damien Miller95def091999-11-25 00:26:21 +1100841 Buffer buffer;
842 int i;
843 char buf[512], *cp;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000844
Damien Miller95def091999-11-25 00:26:21 +1100845 buffer_init(&buffer);
846 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000847 buffer_append(&buffer, buf, strlen(buf));
Damien Miller95def091999-11-25 00:26:21 +1100848 for (i = 0; i < channels_alloc; i++) {
849 Channel *c = &channels[i];
850 switch (c->type) {
851 case SSH_CHANNEL_FREE:
852 case SSH_CHANNEL_X11_LISTENER:
853 case SSH_CHANNEL_PORT_LISTENER:
854 case SSH_CHANNEL_CLOSED:
855 case SSH_CHANNEL_AUTH_SOCKET:
856 continue;
857 case SSH_CHANNEL_OPENING:
858 case SSH_CHANNEL_OPEN:
859 case SSH_CHANNEL_X11_OPEN:
860 case SSH_CHANNEL_INPUT_DRAINING:
861 case SSH_CHANNEL_OUTPUT_DRAINING:
Damien Miller34132e52000-01-14 15:45:46 +1100862 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d)\r\n",
863 c->self, c->remote_name,
864 c->type, c->remote_id,
865 c->istate, buffer_len(&c->input),
866 c->ostate, buffer_len(&c->output));
Damien Miller95def091999-11-25 00:26:21 +1100867 buffer_append(&buffer, buf, strlen(buf));
868 continue;
869 default:
870 fatal("channel_still_open: bad channel type %d", c->type);
871 /* NOTREACHED */
872 }
873 }
874 buffer_append(&buffer, "\0", 1);
875 cp = xstrdup(buffer_ptr(&buffer));
876 buffer_free(&buffer);
877 return cp;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000878}
879
Damien Miller5428f641999-11-25 11:54:57 +1100880/*
881 * Initiate forwarding of connections to local port "port" through the secure
882 * channel to host:port from remote side.
883 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000884
Damien Miller95def091999-11-25 00:26:21 +1100885void
Damien Milleraae6c611999-12-06 11:47:28 +1100886channel_request_local_forwarding(u_short port, const char *host,
Damien Millera34a28b1999-12-14 10:47:15 +1100887 u_short host_port, int gateway_ports)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000888{
Damien Miller34132e52000-01-14 15:45:46 +1100889 int success, ch, sock, on = 1;
890 struct addrinfo hints, *ai, *aitop;
891 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
Damien Miller5428f641999-11-25 11:54:57 +1100892 struct linger linger;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000893
Damien Miller95def091999-11-25 00:26:21 +1100894 if (strlen(host) > sizeof(channels[0].path) - 1)
895 packet_disconnect("Forward host name too long.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000896
Damien Miller5428f641999-11-25 11:54:57 +1100897 /*
Damien Miller34132e52000-01-14 15:45:46 +1100898 * getaddrinfo returns a loopback address if the hostname is
899 * set to NULL and hints.ai_flags is not AI_PASSIVE
Damien Miller5428f641999-11-25 11:54:57 +1100900 */
Damien Miller34132e52000-01-14 15:45:46 +1100901 memset(&hints, 0, sizeof(hints));
902 hints.ai_family = IPv4or6;
903 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
904 hints.ai_socktype = SOCK_STREAM;
905 snprintf(strport, sizeof strport, "%d", port);
906 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
907 packet_disconnect("getaddrinfo: fatal error");
Damien Miller5428f641999-11-25 11:54:57 +1100908
Damien Miller34132e52000-01-14 15:45:46 +1100909 success = 0;
910 for (ai = aitop; ai; ai = ai->ai_next) {
911 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
912 continue;
913 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
914 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
915 error("channel_request_local_forwarding: getnameinfo failed");
916 continue;
917 }
918 /* Create a port to listen for the host. */
919 sock = socket(ai->ai_family, SOCK_STREAM, 0);
920 if (sock < 0) {
921 /* this is no error since kernel may not support ipv6 */
922 verbose("socket: %.100s", strerror(errno));
923 continue;
924 }
925 /*
926 * Set socket options. We would like the socket to disappear
927 * as soon as it has been closed for whatever reason.
928 */
929 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
930 linger.l_onoff = 1;
931 linger.l_linger = 5;
932 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
933 debug("Local forwarding listening on %s port %s.", ntop, strport);
Damien Miller95def091999-11-25 00:26:21 +1100934
Damien Miller34132e52000-01-14 15:45:46 +1100935 /* Bind the socket to the address. */
936 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
937 /* address can be in use ipv6 address is already bound */
Damien Miller3c7eeb22000-03-03 22:35:33 +1100938 if (!ai->ai_next)
939 error("bind: %.100s", strerror(errno));
940 else
941 verbose("bind: %.100s", strerror(errno));
942
Damien Miller34132e52000-01-14 15:45:46 +1100943 close(sock);
944 continue;
945 }
946 /* Start listening for connections on the socket. */
947 if (listen(sock, 5) < 0) {
948 error("listen: %.100s", strerror(errno));
949 close(sock);
950 continue;
951 }
952 /* Allocate a channel number for the socket. */
953 ch = channel_allocate(SSH_CHANNEL_PORT_LISTENER, sock,
954 xstrdup("port listener"));
955 strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
956 channels[ch].host_port = host_port;
957 channels[ch].listening_port = port;
958 success = 1;
959 }
960 if (success == 0)
961 packet_disconnect("cannot listen port: %d", port);
962 freeaddrinfo(aitop);
Damien Miller95def091999-11-25 00:26:21 +1100963}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000964
Damien Miller5428f641999-11-25 11:54:57 +1100965/*
966 * Initiate forwarding of connections to port "port" on remote host through
967 * the secure channel to host:port from local side.
968 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000969
Damien Miller95def091999-11-25 00:26:21 +1100970void
Damien Milleraae6c611999-12-06 11:47:28 +1100971channel_request_remote_forwarding(u_short port, const char *host,
972 u_short remote_port)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000973{
Damien Miller95def091999-11-25 00:26:21 +1100974 int payload_len;
975 /* Record locally that connection to this host/port is permitted. */
976 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
977 fatal("channel_request_remote_forwarding: too many forwards");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000978
Damien Miller95def091999-11-25 00:26:21 +1100979 permitted_opens[num_permitted_opens].host = xstrdup(host);
980 permitted_opens[num_permitted_opens].port = remote_port;
981 num_permitted_opens++;
982
983 /* Send the forward request to the remote side. */
984 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
985 packet_put_int(port);
986 packet_put_string(host, strlen(host));
987 packet_put_int(remote_port);
988 packet_send();
989 packet_write_wait();
990
Damien Miller5428f641999-11-25 11:54:57 +1100991 /*
992 * Wait for response from the remote side. It will send a disconnect
993 * message on failure, and we will never see it here.
994 */
Damien Miller95def091999-11-25 00:26:21 +1100995 packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000996}
997
Damien Miller5428f641999-11-25 11:54:57 +1100998/*
999 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1000 * listening for the port, and sends back a success reply (or disconnect
1001 * message if there was an error). This never returns if there was an error.
1002 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001003
Damien Miller95def091999-11-25 00:26:21 +11001004void
1005channel_input_port_forward_request(int is_root)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001006{
Damien Milleraae6c611999-12-06 11:47:28 +11001007 u_short port, host_port;
Damien Miller95def091999-11-25 00:26:21 +11001008 char *hostname;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001009
Damien Miller95def091999-11-25 00:26:21 +11001010 /* Get arguments from the packet. */
1011 port = packet_get_int();
1012 hostname = packet_get_string(NULL);
1013 host_port = packet_get_int();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001014
Damien Miller5428f641999-11-25 11:54:57 +11001015 /*
1016 * Check that an unprivileged user is not trying to forward a
1017 * privileged port.
1018 */
Damien Miller95def091999-11-25 00:26:21 +11001019 if (port < IPPORT_RESERVED && !is_root)
1020 packet_disconnect("Requested forwarding of port %d but user is not root.",
1021 port);
Damien Millera34a28b1999-12-14 10:47:15 +11001022 /*
1023 * Initiate forwarding,
1024 * bind port to localhost only (gateway ports == 0).
1025 */
1026 channel_request_local_forwarding(port, hostname, host_port, 0);
Damien Miller95def091999-11-25 00:26:21 +11001027
1028 /* Free the argument string. */
1029 xfree(hostname);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001030}
1031
Damien Miller5428f641999-11-25 11:54:57 +11001032/*
1033 * This is called after receiving PORT_OPEN message. This attempts to
1034 * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
1035 * or CHANNEL_OPEN_FAILURE.
1036 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001037
Damien Miller95def091999-11-25 00:26:21 +11001038void
1039channel_input_port_open(int payload_len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001040{
Damien Miller34132e52000-01-14 15:45:46 +11001041 int remote_channel, sock = 0, newch, i;
Damien Milleraae6c611999-12-06 11:47:28 +11001042 u_short host_port;
Damien Miller95def091999-11-25 00:26:21 +11001043 char *host, *originator_string;
Damien Miller95def091999-11-25 00:26:21 +11001044 int host_len, originator_len;
Damien Miller34132e52000-01-14 15:45:46 +11001045 struct addrinfo hints, *ai, *aitop;
1046 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1047 int gaierr;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001048
Damien Miller95def091999-11-25 00:26:21 +11001049 /* Get remote channel number. */
1050 remote_channel = packet_get_int();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001051
Damien Miller95def091999-11-25 00:26:21 +11001052 /* Get host name to connect to. */
1053 host = packet_get_string(&host_len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001054
Damien Miller95def091999-11-25 00:26:21 +11001055 /* Get port to connect to. */
1056 host_port = packet_get_int();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001057
Damien Miller95def091999-11-25 00:26:21 +11001058 /* Get remote originator name. */
Damien Miller5428f641999-11-25 11:54:57 +11001059 if (have_hostname_in_open) {
Damien Miller95def091999-11-25 00:26:21 +11001060 originator_string = packet_get_string(&originator_len);
Damien Miller5428f641999-11-25 11:54:57 +11001061 originator_len += 4; /* size of packet_int */
1062 } else {
Damien Miller95def091999-11-25 00:26:21 +11001063 originator_string = xstrdup("unknown (remote did not supply name)");
Damien Miller5428f641999-11-25 11:54:57 +11001064 originator_len = 0; /* no originator supplied */
1065 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001066
Damien Miller95def091999-11-25 00:26:21 +11001067 packet_integrity_check(payload_len,
Damien Miller5428f641999-11-25 11:54:57 +11001068 4 + 4 + host_len + 4 + originator_len,
Damien Miller95def091999-11-25 00:26:21 +11001069 SSH_MSG_PORT_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001070
Damien Miller95def091999-11-25 00:26:21 +11001071 /* Check if opening that port is permitted. */
1072 if (!all_opens_permitted) {
1073 /* Go trough all permitted ports. */
1074 for (i = 0; i < num_permitted_opens; i++)
1075 if (permitted_opens[i].port == host_port &&
1076 strcmp(permitted_opens[i].host, host) == 0)
1077 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001078
Damien Miller95def091999-11-25 00:26:21 +11001079 /* Check if we found the requested port among those permitted. */
1080 if (i >= num_permitted_opens) {
1081 /* The port is not permitted. */
1082 log("Received request to connect to %.100s:%d, but the request was denied.",
1083 host, host_port);
1084 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1085 packet_put_int(remote_channel);
1086 packet_send();
1087 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001088 }
Damien Miller95def091999-11-25 00:26:21 +11001089
Damien Miller34132e52000-01-14 15:45:46 +11001090 memset(&hints, 0, sizeof(hints));
1091 hints.ai_family = IPv4or6;
1092 hints.ai_socktype = SOCK_STREAM;
1093 snprintf(strport, sizeof strport, "%d", host_port);
1094 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
1095 error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
Damien Miller95def091999-11-25 00:26:21 +11001096 goto fail;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001097 }
Damien Miller34132e52000-01-14 15:45:46 +11001098
1099 for (ai = aitop; ai; ai = ai->ai_next) {
1100 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1101 continue;
1102 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1103 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1104 error("channel_input_port_open: getnameinfo failed");
1105 continue;
1106 }
1107 /* Create the socket. */
1108 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1109 if (sock < 0) {
1110 error("socket: %.100s", strerror(errno));
1111 continue;
1112 }
1113 /* Connect to the host/port. */
1114 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1115 error("connect %.100s port %s: %.100s", ntop, strport,
1116 strerror(errno));
1117 close(sock);
1118 continue; /* fail -- try next */
1119 }
1120 break; /* success */
1121
1122 }
1123 freeaddrinfo(aitop);
1124
1125 if (!ai) {
1126 error("connect %.100s port %d: failed.", host, host_port);
Damien Miller95def091999-11-25 00:26:21 +11001127 goto fail;
1128 }
Damien Miller34132e52000-01-14 15:45:46 +11001129
Damien Miller95def091999-11-25 00:26:21 +11001130 /* Successful connection. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001131
Damien Miller95def091999-11-25 00:26:21 +11001132 /* Allocate a channel for this connection. */
1133 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
1134 channels[newch].remote_id = remote_channel;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001135
Damien Miller95def091999-11-25 00:26:21 +11001136 /* Send a confirmation to the remote host. */
1137 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1138 packet_put_int(remote_channel);
1139 packet_put_int(newch);
1140 packet_send();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001141
Damien Miller95def091999-11-25 00:26:21 +11001142 /* Free the argument string. */
1143 xfree(host);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001144
Damien Miller95def091999-11-25 00:26:21 +11001145 return;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001146
Damien Miller95def091999-11-25 00:26:21 +11001147fail:
1148 /* Free the argument string. */
1149 xfree(host);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001150
Damien Miller95def091999-11-25 00:26:21 +11001151 /* Send refusal to the remote host. */
1152 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1153 packet_put_int(remote_channel);
1154 packet_send();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001155}
1156
Damien Miller5428f641999-11-25 11:54:57 +11001157/*
1158 * Creates an internet domain socket for listening for X11 connections.
1159 * Returns a suitable value for the DISPLAY variable, or NULL if an error
1160 * occurs.
1161 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001162
Damien Miller34132e52000-01-14 15:45:46 +11001163#define NUM_SOCKS 10
1164
Damien Miller95def091999-11-25 00:26:21 +11001165char *
Damien Millera34a28b1999-12-14 10:47:15 +11001166x11_create_display_inet(int screen_number, int x11_display_offset)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001167{
Damien Milleraae6c611999-12-06 11:47:28 +11001168 int display_number, sock;
1169 u_short port;
Damien Miller34132e52000-01-14 15:45:46 +11001170 struct addrinfo hints, *ai, *aitop;
1171 char strport[NI_MAXSERV];
1172 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
1173 char display[512];
Damien Miller95def091999-11-25 00:26:21 +11001174 char hostname[MAXHOSTNAMELEN];
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001175
Damien Millera34a28b1999-12-14 10:47:15 +11001176 for (display_number = x11_display_offset;
Damien Miller95def091999-11-25 00:26:21 +11001177 display_number < MAX_DISPLAYS;
1178 display_number++) {
1179 port = 6000 + display_number;
Damien Miller34132e52000-01-14 15:45:46 +11001180 memset(&hints, 0, sizeof(hints));
1181 hints.ai_family = IPv4or6;
1182 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
1183 hints.ai_socktype = SOCK_STREAM;
1184 snprintf(strport, sizeof strport, "%d", port);
1185 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
1186 error("getaddrinfo: %.100s", gai_strerror(gaierr));
Damien Miller95def091999-11-25 00:26:21 +11001187 return NULL;
1188 }
Damien Miller34132e52000-01-14 15:45:46 +11001189 for (ai = aitop; ai; ai = ai->ai_next) {
1190 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1191 continue;
1192 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1193 if (sock < 0) {
Damien Millere2192732000-01-17 13:22:55 +11001194 if (errno != EINVAL) {
1195 error("socket: %.100s", strerror(errno));
1196 return NULL;
1197 } else {
1198 debug("Socket family %d not supported [X11 disp create]", ai->ai_family);
1199 continue;
1200 }
Damien Miller34132e52000-01-14 15:45:46 +11001201 }
1202 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1203 debug("bind port %d: %.100s", port, strerror(errno));
1204 shutdown(sock, SHUT_RDWR);
1205 close(sock);
Damien Miller3c7eeb22000-03-03 22:35:33 +11001206
1207 if (ai->ai_next)
1208 continue;
1209
Damien Miller34132e52000-01-14 15:45:46 +11001210 for (n = 0; n < num_socks; n++) {
1211 shutdown(socks[n], SHUT_RDWR);
1212 close(socks[n]);
1213 }
1214 num_socks = 0;
1215 break;
1216 }
1217 socks[num_socks++] = sock;
Damien Miller7bcb0892000-03-11 20:45:40 +11001218#ifndef DONT_TRY_OTHER_AF
Damien Miller34132e52000-01-14 15:45:46 +11001219 if (num_socks == NUM_SOCKS)
1220 break;
Damien Miller7bcb0892000-03-11 20:45:40 +11001221#else
1222 break;
1223#endif
Damien Miller95def091999-11-25 00:26:21 +11001224 }
Damien Miller34132e52000-01-14 15:45:46 +11001225 if (num_socks > 0)
1226 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001227 }
Damien Miller95def091999-11-25 00:26:21 +11001228 if (display_number >= MAX_DISPLAYS) {
1229 error("Failed to allocate internet-domain X11 display socket.");
1230 return NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001231 }
Damien Miller95def091999-11-25 00:26:21 +11001232 /* Start listening for connections on the socket. */
Damien Miller34132e52000-01-14 15:45:46 +11001233 for (n = 0; n < num_socks; n++) {
1234 sock = socks[n];
1235 if (listen(sock, 5) < 0) {
1236 error("listen: %.100s", strerror(errno));
1237 shutdown(sock, SHUT_RDWR);
1238 close(sock);
1239 return NULL;
1240 }
Damien Miller95def091999-11-25 00:26:21 +11001241 }
Damien Miller34132e52000-01-14 15:45:46 +11001242
Damien Miller95def091999-11-25 00:26:21 +11001243 /* Set up a suitable value for the DISPLAY variable. */
Damien Miller76112de1999-12-21 11:18:08 +11001244
Damien Miller95def091999-11-25 00:26:21 +11001245 if (gethostname(hostname, sizeof(hostname)) < 0)
1246 fatal("gethostname: %.100s", strerror(errno));
Damien Miller76112de1999-12-21 11:18:08 +11001247
1248#ifdef IPADDR_IN_DISPLAY
1249 /*
1250 * HPUX detects the local hostname in the DISPLAY variable and tries
1251 * to set up a shared memory connection to the server, which it
1252 * incorrectly supposes to be local.
1253 *
1254 * The workaround - as used in later $$H and other programs - is
1255 * is to set display to the host's IP address.
1256 */
1257 {
1258 struct hostent *he;
1259 struct in_addr my_addr;
1260
1261 he = gethostbyname(hostname);
1262 if (he == NULL) {
1263 error("[X11-broken-fwd-hostname-workaround] Could not get "
1264 "IP address for hostname %s.", hostname);
1265
1266 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
1267 "Could not get IP address for hostname %s.", hostname);
1268
1269 shutdown(sock, SHUT_RDWR);
1270 close(sock);
1271
1272 return NULL;
1273 }
1274
1275 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
1276
1277 /* Set DISPLAY to <ip address>:screen.display */
Damien Miller34132e52000-01-14 15:45:46 +11001278 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
Damien Miller76112de1999-12-21 11:18:08 +11001279 display_number, screen_number);
1280 }
1281#else /* IPADDR_IN_DISPLAY */
1282 /* Just set DISPLAY to hostname:screen.display */
Damien Miller34132e52000-01-14 15:45:46 +11001283 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
Damien Miller76112de1999-12-21 11:18:08 +11001284 display_number, screen_number);
1285#endif /* IPADDR_IN_DISPLAY */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001286
Damien Miller34132e52000-01-14 15:45:46 +11001287 /* Allocate a channel for each socket. */
1288 for (n = 0; n < num_socks; n++) {
1289 sock = socks[n];
1290 (void) channel_allocate(SSH_CHANNEL_X11_LISTENER, sock,
1291 xstrdup("X11 inet listener"));
1292 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001293
Damien Miller95def091999-11-25 00:26:21 +11001294 /* Return a suitable value for the DISPLAY environment variable. */
Damien Miller34132e52000-01-14 15:45:46 +11001295 return xstrdup(display);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001296}
1297
1298#ifndef X_UNIX_PATH
1299#define X_UNIX_PATH "/tmp/.X11-unix/X"
1300#endif
1301
1302static
1303int
Damien Miller81b25cf1999-12-07 16:47:28 +11001304connect_local_xsocket(unsigned int dnr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001305{
Damien Miller95def091999-11-25 00:26:21 +11001306 static const char *const x_sockets[] = {
1307 X_UNIX_PATH "%u",
1308 "/var/X/.X11-unix/X" "%u",
1309 "/usr/spool/sockets/X11/" "%u",
1310 NULL
1311 };
1312 int sock;
1313 struct sockaddr_un addr;
1314 const char *const * path;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001315
Damien Miller95def091999-11-25 00:26:21 +11001316 for (path = x_sockets; *path; ++path) {
1317 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1318 if (sock < 0)
1319 error("socket: %.100s", strerror(errno));
1320 memset(&addr, 0, sizeof(addr));
1321 addr.sun_family = AF_UNIX;
1322 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
1323 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
1324 return sock;
1325 close(sock);
1326 }
1327 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
1328 return -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001329}
1330
1331
Damien Miller5428f641999-11-25 11:54:57 +11001332/*
1333 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
1334 * the remote channel number. We should do whatever we want, and respond
1335 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
1336 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001337
Damien Miller95def091999-11-25 00:26:21 +11001338void
1339x11_input_open(int payload_len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001340{
Damien Miller34132e52000-01-14 15:45:46 +11001341 int remote_channel, display_number, sock = 0, newch;
Damien Miller95def091999-11-25 00:26:21 +11001342 const char *display;
Damien Miller95def091999-11-25 00:26:21 +11001343 char buf[1024], *cp, *remote_host;
Damien Miller95def091999-11-25 00:26:21 +11001344 int remote_len;
Damien Miller34132e52000-01-14 15:45:46 +11001345 struct addrinfo hints, *ai, *aitop;
1346 char strport[NI_MAXSERV];
1347 int gaierr;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001348
Damien Miller95def091999-11-25 00:26:21 +11001349 /* Get remote channel number. */
1350 remote_channel = packet_get_int();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001351
Damien Miller95def091999-11-25 00:26:21 +11001352 /* Get remote originator name. */
Damien Miller5428f641999-11-25 11:54:57 +11001353 if (have_hostname_in_open) {
Damien Miller95def091999-11-25 00:26:21 +11001354 remote_host = packet_get_string(&remote_len);
Damien Miller5428f641999-11-25 11:54:57 +11001355 remote_len += 4;
1356 } else {
Damien Miller95def091999-11-25 00:26:21 +11001357 remote_host = xstrdup("unknown (remote did not supply name)");
Damien Miller5428f641999-11-25 11:54:57 +11001358 remote_len = 0;
1359 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001360
Damien Miller95def091999-11-25 00:26:21 +11001361 debug("Received X11 open request.");
Damien Miller5428f641999-11-25 11:54:57 +11001362 packet_integrity_check(payload_len, 4 + remote_len, SSH_SMSG_X11_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001363
Damien Miller95def091999-11-25 00:26:21 +11001364 /* Try to open a socket for the local X server. */
1365 display = getenv("DISPLAY");
1366 if (!display) {
1367 error("DISPLAY not set.");
1368 goto fail;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001369 }
Damien Miller5428f641999-11-25 11:54:57 +11001370 /*
1371 * Now we decode the value of the DISPLAY variable and make a
1372 * connection to the real X server.
1373 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001374
Damien Miller5428f641999-11-25 11:54:57 +11001375 /*
1376 * Check if it is a unix domain socket. Unix domain displays are in
1377 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
1378 */
Damien Miller95def091999-11-25 00:26:21 +11001379 if (strncmp(display, "unix:", 5) == 0 ||
1380 display[0] == ':') {
1381 /* Connect to the unix domain socket. */
1382 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
1383 error("Could not parse display number from DISPLAY: %.100s",
1384 display);
1385 goto fail;
1386 }
1387 /* Create a socket. */
1388 sock = connect_local_xsocket(display_number);
1389 if (sock < 0)
1390 goto fail;
1391
1392 /* OK, we now have a connection to the display. */
1393 goto success;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001394 }
Damien Miller5428f641999-11-25 11:54:57 +11001395 /*
1396 * Connect to an inet socket. The DISPLAY value is supposedly
1397 * hostname:d[.s], where hostname may also be numeric IP address.
1398 */
Damien Miller95def091999-11-25 00:26:21 +11001399 strncpy(buf, display, sizeof(buf));
1400 buf[sizeof(buf) - 1] = 0;
1401 cp = strchr(buf, ':');
1402 if (!cp) {
1403 error("Could not find ':' in DISPLAY: %.100s", display);
1404 goto fail;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001405 }
Damien Miller95def091999-11-25 00:26:21 +11001406 *cp = 0;
Damien Miller5428f641999-11-25 11:54:57 +11001407 /* buf now contains the host name. But first we parse the display number. */
Damien Miller95def091999-11-25 00:26:21 +11001408 if (sscanf(cp + 1, "%d", &display_number) != 1) {
1409 error("Could not parse display number from DISPLAY: %.100s",
1410 display);
1411 goto fail;
1412 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001413
Damien Miller34132e52000-01-14 15:45:46 +11001414 /* Look up the host address */
1415 memset(&hints, 0, sizeof(hints));
1416 hints.ai_family = IPv4or6;
1417 hints.ai_socktype = SOCK_STREAM;
1418 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
1419 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
1420 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
Damien Miller95def091999-11-25 00:26:21 +11001421 goto fail;
1422 }
Damien Miller34132e52000-01-14 15:45:46 +11001423 for (ai = aitop; ai; ai = ai->ai_next) {
1424 /* Create a socket. */
1425 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1426 if (sock < 0) {
1427 debug("socket: %.100s", strerror(errno));
1428 continue;
1429 }
Damien Miller95def091999-11-25 00:26:21 +11001430 /* Connect it to the display. */
Damien Miller34132e52000-01-14 15:45:46 +11001431 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1432 debug("connect %.100s port %d: %.100s", buf, 6000 + display_number,
1433 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +11001434 close(sock);
Damien Miller34132e52000-01-14 15:45:46 +11001435 continue;
1436 }
1437 /* Success */
1438 break;
1439
1440 } /* (ai = aitop, ai; ai = ai->ai_next) */
1441 freeaddrinfo(aitop);
1442 if (!ai) {
1443 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
1444 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +11001445 goto fail;
1446 }
1447success:
1448 /* We have successfully obtained a connection to the real X display. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001449
Damien Miller95def091999-11-25 00:26:21 +11001450 /* Allocate a channel for this connection. */
1451 if (x11_saved_proto == NULL)
1452 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, remote_host);
1453 else
1454 newch = channel_allocate(SSH_CHANNEL_X11_OPEN, sock, remote_host);
1455 channels[newch].remote_id = remote_channel;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001456
Damien Miller95def091999-11-25 00:26:21 +11001457 /* Send a confirmation to the remote host. */
1458 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1459 packet_put_int(remote_channel);
1460 packet_put_int(newch);
1461 packet_send();
1462
1463 return;
1464
1465fail:
1466 /* Send refusal to the remote host. */
1467 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1468 packet_put_int(remote_channel);
1469 packet_send();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001470}
1471
Damien Miller5428f641999-11-25 11:54:57 +11001472/*
1473 * Requests forwarding of X11 connections, generates fake authentication
1474 * data, and enables authentication spoofing.
1475 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001476
Damien Miller95def091999-11-25 00:26:21 +11001477void
1478x11_request_forwarding_with_spoofing(const char *proto, const char *data)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001479{
Damien Miller95def091999-11-25 00:26:21 +11001480 unsigned int data_len = (unsigned int) strlen(data) / 2;
1481 unsigned int i, value;
1482 char *new_data;
1483 int screen_number;
1484 const char *cp;
1485 u_int32_t rand = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001486
Damien Miller95def091999-11-25 00:26:21 +11001487 cp = getenv("DISPLAY");
1488 if (cp)
1489 cp = strchr(cp, ':');
1490 if (cp)
1491 cp = strchr(cp, '.');
1492 if (cp)
1493 screen_number = atoi(cp + 1);
1494 else
1495 screen_number = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001496
Damien Miller95def091999-11-25 00:26:21 +11001497 /* Save protocol name. */
1498 x11_saved_proto = xstrdup(proto);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001499
Damien Miller5428f641999-11-25 11:54:57 +11001500 /*
1501 * Extract real authentication data and generate fake data of the
1502 * same length.
1503 */
Damien Miller95def091999-11-25 00:26:21 +11001504 x11_saved_data = xmalloc(data_len);
1505 x11_fake_data = xmalloc(data_len);
1506 for (i = 0; i < data_len; i++) {
1507 if (sscanf(data + 2 * i, "%2x", &value) != 1)
1508 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
1509 if (i % 4 == 0)
1510 rand = arc4random();
1511 x11_saved_data[i] = value;
1512 x11_fake_data[i] = rand & 0xff;
1513 rand >>= 8;
1514 }
1515 x11_saved_data_len = data_len;
1516 x11_fake_data_len = data_len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001517
Damien Miller95def091999-11-25 00:26:21 +11001518 /* Convert the fake data into hex. */
1519 new_data = xmalloc(2 * data_len + 1);
1520 for (i = 0; i < data_len; i++)
1521 sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001522
Damien Miller95def091999-11-25 00:26:21 +11001523 /* Send the request packet. */
1524 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
1525 packet_put_string(proto, strlen(proto));
1526 packet_put_string(new_data, strlen(new_data));
1527 packet_put_int(screen_number);
1528 packet_send();
1529 packet_write_wait();
1530 xfree(new_data);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001531}
1532
1533/* Sends a message to the server to request authentication fd forwarding. */
1534
Damien Miller95def091999-11-25 00:26:21 +11001535void
1536auth_request_forwarding()
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001537{
Damien Miller95def091999-11-25 00:26:21 +11001538 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
1539 packet_send();
1540 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001541}
1542
Damien Miller5428f641999-11-25 11:54:57 +11001543/*
1544 * Returns the name of the forwarded authentication socket. Returns NULL if
1545 * there is no forwarded authentication socket. The returned value points to
1546 * a static buffer.
1547 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001548
Damien Miller95def091999-11-25 00:26:21 +11001549char *
1550auth_get_socket_name()
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001551{
Damien Miller95def091999-11-25 00:26:21 +11001552 return channel_forwarded_auth_socket_name;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001553}
1554
1555/* removes the agent forwarding socket */
1556
Damien Miller95def091999-11-25 00:26:21 +11001557void
1558cleanup_socket(void)
1559{
1560 remove(channel_forwarded_auth_socket_name);
1561 rmdir(channel_forwarded_auth_socket_dir);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001562}
1563
Damien Miller5428f641999-11-25 11:54:57 +11001564/*
1565 * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
1566 * This starts forwarding authentication requests.
1567 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001568
Damien Miller95def091999-11-25 00:26:21 +11001569void
1570auth_input_request_forwarding(struct passwd * pw)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001571{
Damien Miller95def091999-11-25 00:26:21 +11001572 int sock, newch;
1573 struct sockaddr_un sunaddr;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001574
Damien Miller95def091999-11-25 00:26:21 +11001575 if (auth_get_socket_name() != NULL)
1576 fatal("Protocol error: authentication forwarding requested twice.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001577
Damien Miller95def091999-11-25 00:26:21 +11001578 /* Temporarily drop privileged uid for mkdir/bind. */
1579 temporarily_use_uid(pw->pw_uid);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001580
Damien Miller95def091999-11-25 00:26:21 +11001581 /* Allocate a buffer for the socket name, and format the name. */
1582 channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
1583 channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
1584 strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001585
Damien Miller95def091999-11-25 00:26:21 +11001586 /* Create private directory for socket */
1587 if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL)
1588 packet_disconnect("mkdtemp: %.100s", strerror(errno));
1589 snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
1590 channel_forwarded_auth_socket_dir, (int) getpid());
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001591
Damien Miller95def091999-11-25 00:26:21 +11001592 if (atexit(cleanup_socket) < 0) {
1593 int saved = errno;
1594 cleanup_socket();
1595 packet_disconnect("socket: %.100s", strerror(saved));
1596 }
1597 /* Create the socket. */
1598 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1599 if (sock < 0)
1600 packet_disconnect("socket: %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001601
Damien Miller95def091999-11-25 00:26:21 +11001602 /* Bind it to the name. */
1603 memset(&sunaddr, 0, sizeof(sunaddr));
1604 sunaddr.sun_family = AF_UNIX;
1605 strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
1606 sizeof(sunaddr.sun_path));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001607
Damien Miller95def091999-11-25 00:26:21 +11001608 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
1609 packet_disconnect("bind: %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001610
Damien Miller95def091999-11-25 00:26:21 +11001611 /* Restore the privileged uid. */
1612 restore_uid();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001613
Damien Miller95def091999-11-25 00:26:21 +11001614 /* Start listening on the socket. */
1615 if (listen(sock, 5) < 0)
1616 packet_disconnect("listen: %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001617
Damien Miller95def091999-11-25 00:26:21 +11001618 /* Allocate a channel for the authentication agent socket. */
1619 newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock,
1620 xstrdup("auth socket"));
Damien Miller037a0dc1999-12-07 15:38:31 +11001621 strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
1622 sizeof(channels[newch].path));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001623}
1624
1625/* This is called to process an SSH_SMSG_AGENT_OPEN message. */
1626
Damien Miller95def091999-11-25 00:26:21 +11001627void
1628auth_input_open_request()
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001629{
Damien Miller95def091999-11-25 00:26:21 +11001630 int remch, sock, newch;
1631 char *dummyname;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001632
Damien Miller95def091999-11-25 00:26:21 +11001633 /* Read the remote channel number from the message. */
1634 remch = packet_get_int();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001635
Damien Miller5428f641999-11-25 11:54:57 +11001636 /*
1637 * Get a connection to the local authentication agent (this may again
1638 * get forwarded).
1639 */
Damien Miller95def091999-11-25 00:26:21 +11001640 sock = ssh_get_authentication_socket();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001641
Damien Miller5428f641999-11-25 11:54:57 +11001642 /*
1643 * If we could not connect the agent, send an error message back to
1644 * the server. This should never happen unless the agent dies,
1645 * because authentication forwarding is only enabled if we have an
1646 * agent.
1647 */
Damien Miller95def091999-11-25 00:26:21 +11001648 if (sock < 0) {
1649 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1650 packet_put_int(remch);
1651 packet_send();
1652 return;
1653 }
1654 debug("Forwarding authentication connection.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001655
Damien Miller5428f641999-11-25 11:54:57 +11001656 /*
1657 * Dummy host name. This will be freed when the channel is freed; it
1658 * will still be valid in the packet_put_string below since the
1659 * channel cannot yet be freed at that point.
1660 */
Damien Miller95def091999-11-25 00:26:21 +11001661 dummyname = xstrdup("authentication agent connection");
1662
1663 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
1664 channels[newch].remote_id = remch;
1665
1666 /* Send a confirmation to the remote host. */
1667 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1668 packet_put_int(remch);
1669 packet_put_int(newch);
1670 packet_send();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001671}