Annotation of src/usr.bin/ssh/channels.c, Revision 1.45
1.1 deraadt 1: /*
1.26 deraadt 2: *
3: * channels.c
4: *
5: * Author: Tatu Ylonen <ylo@cs.hut.fi>
6: *
7: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: * All rights reserved
9: *
10: * Created: Fri Mar 24 16:35:24 1995 ylo
11: *
12: * This file contains functions for generic socket connection forwarding.
13: * There is also code for initiating connection forwarding for X11 connections,
14: * arbitrary tcp/ip connections, and the authentication agent connection.
15: *
1.44 markus 16: * SSH2 support added by Markus Friedl.
1.26 deraadt 17: */
1.1 deraadt 18:
19: #include "includes.h"
1.45 ! markus 20: RCSID("$Id: channels.c,v 1.44 2000/04/03 07:07:15 markus Exp $");
1.1 deraadt 21:
22: #include "ssh.h"
23: #include "packet.h"
24: #include "xmalloc.h"
25: #include "buffer.h"
26: #include "authfd.h"
27: #include "uidswap.h"
1.20 markus 28: #include "readconf.h"
1.3 deraadt 29: #include "servconf.h"
1.1 deraadt 30:
1.14 markus 31: #include "channels.h"
32: #include "nchan.h"
33: #include "compat.h"
34:
1.44 markus 35: #include "ssh2.h"
36:
1.1 deraadt 37: /* Maximum number of fake X11 displays to try. */
38: #define MAX_DISPLAYS 1000
39:
1.12 markus 40: /* Max len of agent socket */
41: #define MAX_SOCKET_NAME 100
42:
1.41 markus 43: /* default buffer for tcp-fwd-channel */
44: #define CHAN_WINDOW_DEFAULT (8*1024)
45: #define CHAN_PACKET_DEFAULT (CHAN_WINDOW_DEFAULT/2)
46:
1.27 markus 47: /*
48: * Pointer to an array containing all allocated channels. The array is
49: * dynamically extended as needed.
50: */
1.1 deraadt 51: static Channel *channels = NULL;
52:
1.27 markus 53: /*
54: * Size of the channel array. All slots of the array must always be
55: * initialized (at least the type field); unused slots are marked with type
56: * SSH_CHANNEL_FREE.
57: */
1.1 deraadt 58: static int channels_alloc = 0;
59:
1.27 markus 60: /*
61: * Maximum file descriptor value used in any of the channels. This is
62: * updated in channel_allocate.
63: */
1.1 deraadt 64: static int channel_max_fd_value = 0;
65:
1.12 markus 66: /* Name and directory of socket for authentication agent forwarding. */
1.1 deraadt 67: static char *channel_forwarded_auth_socket_name = NULL;
1.25 markus 68: static char *channel_forwarded_auth_socket_dir = NULL;
1.1 deraadt 69:
70: /* Saved X11 authentication protocol name. */
71: char *x11_saved_proto = NULL;
72:
73: /* Saved X11 authentication data. This is the real data. */
74: char *x11_saved_data = NULL;
75: unsigned int x11_saved_data_len = 0;
76:
1.27 markus 77: /*
78: * Fake X11 authentication data. This is what the server will be sending us;
79: * we should replace any occurrences of this by the real data.
80: */
1.1 deraadt 81: char *x11_fake_data = NULL;
82: unsigned int x11_fake_data_len;
83:
1.27 markus 84: /*
85: * Data structure for storing which hosts are permitted for forward requests.
86: * The local sides of any remote forwards are stored in this array to prevent
87: * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
88: * network (which might be behind a firewall).
89: */
1.25 markus 90: typedef struct {
1.41 markus 91: char *host_to_connect; /* Connect to 'host'. */
92: u_short port_to_connect; /* Connect to 'port'. */
93: u_short listen_port; /* Remote side should listen port number. */
1.1 deraadt 94: } ForwardPermission;
95:
96: /* List of all permitted host/port pairs to connect. */
97: static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
98: /* Number of permitted host/port pairs in the array. */
99: static int num_permitted_opens = 0;
1.27 markus 100: /*
101: * If this is true, all opens are permitted. This is the case on the server
102: * on which we have to trust the client anyway, and the user could do
103: * anything after logging in anyway.
104: */
1.1 deraadt 105: static int all_opens_permitted = 0;
106:
107: /* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */
108: static int have_hostname_in_open = 0;
109:
110: /* Sets specific protocol options. */
111:
1.25 markus 112: void
113: channel_set_options(int hostname_in_open)
1.1 deraadt 114: {
1.25 markus 115: have_hostname_in_open = hostname_in_open;
1.1 deraadt 116: }
117:
1.27 markus 118: /*
119: * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
120: * called by the server, because the user could connect to any port anyway,
121: * and the server has no way to know but to trust the client anyway.
122: */
1.1 deraadt 123:
1.25 markus 124: void
125: channel_permit_all_opens()
1.1 deraadt 126: {
1.25 markus 127: all_opens_permitted = 1;
1.1 deraadt 128: }
129:
1.41 markus 130: /* lookup channel by id */
131:
132: Channel *
133: channel_lookup(int id)
134: {
135: Channel *c;
136: if (id < 0 && id > channels_alloc) {
137: log("channel_lookup: %d: bad id", id);
138: return NULL;
139: }
140: c = &channels[id];
141: if (c->type == SSH_CHANNEL_FREE) {
142: log("channel_lookup: %d: bad id: channel free", id);
143: return NULL;
144: }
145: return c;
146: }
147:
1.27 markus 148: /*
149: * Allocate a new channel object and set its type and socket. This will cause
150: * remote_name to be freed.
151: */
1.1 deraadt 152:
1.25 markus 153: int
1.41 markus 154: channel_new(char *ctype, int type, int rfd, int wfd, int efd,
155: int window, int maxpack, int extended_usage, char *remote_name)
1.1 deraadt 156: {
1.25 markus 157: int i, found;
158: Channel *c;
1.1 deraadt 159:
1.25 markus 160: /* Update the maximum file descriptor value. */
1.41 markus 161: if (rfd > channel_max_fd_value)
162: channel_max_fd_value = rfd;
163: if (wfd > channel_max_fd_value)
164: channel_max_fd_value = wfd;
165: if (efd > channel_max_fd_value)
166: channel_max_fd_value = efd;
1.27 markus 167: /* XXX set close-on-exec -markus */
1.25 markus 168:
169: /* Do initial allocation if this is the first call. */
170: if (channels_alloc == 0) {
1.44 markus 171: chan_init();
1.25 markus 172: channels_alloc = 10;
173: channels = xmalloc(channels_alloc * sizeof(Channel));
174: for (i = 0; i < channels_alloc; i++)
175: channels[i].type = SSH_CHANNEL_FREE;
1.27 markus 176: /*
177: * Kludge: arrange a call to channel_stop_listening if we
178: * terminate with fatal().
179: */
1.25 markus 180: fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
181: }
182: /* Try to find a free slot where to put the new channel. */
183: for (found = -1, i = 0; i < channels_alloc; i++)
184: if (channels[i].type == SSH_CHANNEL_FREE) {
185: /* Found a free slot. */
186: found = i;
187: break;
188: }
189: if (found == -1) {
1.27 markus 190: /* There are no free slots. Take last+1 slot and expand the array. */
1.25 markus 191: found = channels_alloc;
192: channels_alloc += 10;
193: debug("channel: expanding %d", channels_alloc);
194: channels = xrealloc(channels, channels_alloc * sizeof(Channel));
195: for (i = found; i < channels_alloc; i++)
196: channels[i].type = SSH_CHANNEL_FREE;
197: }
198: /* Initialize and return new channel number. */
199: c = &channels[found];
200: buffer_init(&c->input);
201: buffer_init(&c->output);
1.41 markus 202: buffer_init(&c->extended);
1.25 markus 203: chan_init_iostates(c);
204: c->self = found;
205: c->type = type;
1.41 markus 206: c->ctype = ctype;
207: c->local_window = window;
208: c->local_window_max = window;
209: c->local_consumed = 0;
210: c->local_maxpacket = maxpack;
211: c->remote_window = 0;
212: c->remote_maxpacket = 0;
213: c->rfd = rfd;
214: c->wfd = wfd;
215: c->sock = (rfd == wfd) ? rfd : -1;
216: c->efd = efd;
217: c->extended_usage = extended_usage;
1.25 markus 218: c->remote_id = -1;
219: c->remote_name = remote_name;
1.41 markus 220: c->remote_window = 0;
221: c->remote_maxpacket = 0;
222: c->cb_fn = NULL;
223: c->cb_arg = NULL;
224: c->cb_event = 0;
225: c->dettach_user = NULL;
1.25 markus 226: debug("channel %d: new [%s]", found, remote_name);
227: return found;
1.1 deraadt 228: }
1.41 markus 229: int
230: channel_allocate(int type, int sock, char *remote_name)
231: {
232: return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name);
233: }
1.1 deraadt 234:
235: /* Free the channel and close its socket. */
236:
1.25 markus 237: void
1.41 markus 238: channel_free(int id)
1.1 deraadt 239: {
1.41 markus 240: Channel *c = channel_lookup(id);
241: if (c == NULL)
242: packet_disconnect("channel free: bad local channel %d", id);
243: debug("channel_free: channel %d: status: %s", id, channel_open_message());
1.44 markus 244: if (c->dettach_user != NULL) {
245: debug("channel_free: channel %d: dettaching channel user", id);
246: c->dettach_user(c->self, NULL);
247: }
1.43 markus 248: if (c->sock != -1) {
1.41 markus 249: shutdown(c->sock, SHUT_RDWR);
1.42 markus 250: close(c->sock);
1.44 markus 251: c->sock = -1;
252: }
253: if (compat20) {
254: if (c->rfd != -1) {
255: close(c->rfd);
256: c->rfd = -1;
257: }
258: if (c->wfd != -1) {
259: close(c->wfd);
260: c->wfd = -1;
261: }
262: if (c->efd != -1) {
263: close(c->efd);
264: c->efd = -1;
265: }
1.42 markus 266: }
1.41 markus 267: buffer_free(&c->input);
268: buffer_free(&c->output);
269: buffer_free(&c->extended);
270: c->type = SSH_CHANNEL_FREE;
271: if (c->remote_name) {
272: xfree(c->remote_name);
273: c->remote_name = NULL;
1.25 markus 274: }
1.1 deraadt 275: }
276:
1.27 markus 277: /*
1.41 markus 278: * 'channel_pre*' are called just before select() to add any bits relevant to
279: * channels in the select bitmasks.
280: */
281: /*
282: * 'channel_post*': perform any appropriate operations for channels which
283: * have events pending.
1.27 markus 284: */
1.41 markus 285: typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
286: chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
287: chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
288:
289: void
290: channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
291: {
292: FD_SET(c->sock, readset);
293: }
294:
295: void
296: channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
297: {
298: if (buffer_len(&c->input) < packet_get_maxsize())
299: FD_SET(c->sock, readset);
300: if (buffer_len(&c->output) > 0)
301: FD_SET(c->sock, writeset);
302: }
1.1 deraadt 303:
1.41 markus 304: void
305: channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
306: {
307: /* test whether sockets are 'alive' for read/write */
308: if (c->istate == CHAN_INPUT_OPEN)
309: if (buffer_len(&c->input) < packet_get_maxsize())
310: FD_SET(c->sock, readset);
311: if (c->ostate == CHAN_OUTPUT_OPEN ||
312: c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
313: if (buffer_len(&c->output) > 0) {
314: FD_SET(c->sock, writeset);
315: } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
316: chan_obuf_empty(c);
317: }
318: }
319: }
320:
321: void
1.44 markus 322: channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
323: {
324: if (c->istate == CHAN_INPUT_OPEN &&
325: c->remote_window > 0 &&
326: buffer_len(&c->input) < c->remote_window)
327: FD_SET(c->rfd, readset);
328: if (c->ostate == CHAN_OUTPUT_OPEN ||
329: c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
330: if (buffer_len(&c->output) > 0) {
331: FD_SET(c->wfd, writeset);
332: } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
333: chan_obuf_empty(c);
334: }
335: }
336: /** XXX check close conditions, too */
337: if (c->efd != -1) {
338: if (c->extended_usage == CHAN_EXTENDED_WRITE &&
339: buffer_len(&c->extended) > 0)
340: FD_SET(c->efd, writeset);
341: else if (c->extended_usage == CHAN_EXTENDED_READ &&
342: buffer_len(&c->extended) < c->remote_window)
343: FD_SET(c->efd, readset);
344: }
345: }
346:
347: void
1.41 markus 348: channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
349: {
350: if (buffer_len(&c->input) == 0) {
351: packet_start(SSH_MSG_CHANNEL_CLOSE);
352: packet_put_int(c->remote_id);
353: packet_send();
354: c->type = SSH_CHANNEL_CLOSED;
355: debug("Closing channel %d after input drain.", c->self);
356: }
357: }
358:
359: void
360: channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
361: {
362: if (buffer_len(&c->output) == 0)
363: channel_free(c->self);
364: else
365: FD_SET(c->sock, writeset);
366: }
367:
368: /*
369: * This is a special state for X11 authentication spoofing. An opened X11
370: * connection (when authentication spoofing is being done) remains in this
371: * state until the first packet has been completely read. The authentication
372: * data in that packet is then substituted by the real data if it matches the
373: * fake data, and the channel is put into normal mode.
374: */
375: int
376: x11_open_helper(Channel *c)
1.1 deraadt 377: {
1.25 markus 378: unsigned char *ucp;
379: unsigned int proto_len, data_len;
380:
1.41 markus 381: /* Check if the fixed size part of the packet is in buffer. */
382: if (buffer_len(&c->output) < 12)
383: return 0;
384:
385: /* Parse the lengths of variable-length fields. */
386: ucp = (unsigned char *) buffer_ptr(&c->output);
387: if (ucp[0] == 0x42) { /* Byte order MSB first. */
388: proto_len = 256 * ucp[6] + ucp[7];
389: data_len = 256 * ucp[8] + ucp[9];
390: } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
391: proto_len = ucp[6] + 256 * ucp[7];
392: data_len = ucp[8] + 256 * ucp[9];
393: } else {
394: debug("Initial X11 packet contains bad byte order byte: 0x%x",
395: ucp[0]);
396: return -1;
397: }
398:
399: /* Check if the whole packet is in buffer. */
400: if (buffer_len(&c->output) <
401: 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
402: return 0;
403:
404: /* Check if authentication protocol matches. */
405: if (proto_len != strlen(x11_saved_proto) ||
406: memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
407: debug("X11 connection uses different authentication protocol.");
408: return -1;
409: }
410: /* Check if authentication data matches our fake data. */
411: if (data_len != x11_fake_data_len ||
412: memcmp(ucp + 12 + ((proto_len + 3) & ~3),
413: x11_fake_data, x11_fake_data_len) != 0) {
414: debug("X11 auth data does not match fake data.");
415: return -1;
416: }
417: /* Check fake data length */
418: if (x11_fake_data_len != x11_saved_data_len) {
419: error("X11 fake_data_len %d != saved_data_len %d",
420: x11_fake_data_len, x11_saved_data_len);
421: return -1;
422: }
423: /*
424: * Received authentication protocol and data match
425: * our fake data. Substitute the fake data with real
426: * data.
427: */
428: memcpy(ucp + 12 + ((proto_len + 3) & ~3),
429: x11_saved_data, x11_saved_data_len);
430: return 1;
431: }
432:
433: void
434: channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
435: {
436: int ret = x11_open_helper(c);
437: if (ret == 1) {
438: /* Start normal processing for the channel. */
439: c->type = SSH_CHANNEL_OPEN;
440: } else if (ret == -1) {
441: /*
442: * We have received an X11 connection that has bad
443: * authentication information.
444: */
445: log("X11 connection rejected because of wrong authentication.\r\n");
446: buffer_clear(&c->input);
447: buffer_clear(&c->output);
448: close(c->sock);
449: c->sock = -1;
450: c->type = SSH_CHANNEL_CLOSED;
451: packet_start(SSH_MSG_CHANNEL_CLOSE);
452: packet_put_int(c->remote_id);
453: packet_send();
454: }
455: }
1.25 markus 456:
1.41 markus 457: void
458: channel_pre_x11_open_15(Channel *c, fd_set * readset, fd_set * writeset)
459: {
460: int ret = x11_open_helper(c);
461: if (ret == 1) {
462: c->type = SSH_CHANNEL_OPEN;
463: } else if (ret == -1) {
464: debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
465: chan_read_failed(c);
466: chan_write_failed(c);
467: debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
468: }
469: }
1.25 markus 470:
1.41 markus 471: /* This is our fake X11 server socket. */
472: void
473: channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
474: {
475: struct sockaddr addr;
476: int newsock, newch;
477: socklen_t addrlen;
478: char buf[16384], *remote_hostname;
1.25 markus 479:
1.41 markus 480: if (FD_ISSET(c->sock, readset)) {
481: debug("X11 connection requested.");
482: addrlen = sizeof(addr);
483: newsock = accept(c->sock, &addr, &addrlen);
484: if (newsock < 0) {
485: error("accept: %.100s", strerror(errno));
486: return;
487: }
488: remote_hostname = get_remote_hostname(newsock);
489: snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
490: remote_hostname, get_peer_port(newsock));
491: xfree(remote_hostname);
492: newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
493: xstrdup(buf));
494: packet_start(SSH_SMSG_X11_OPEN);
495: packet_put_int(newch);
496: if (have_hostname_in_open)
497: packet_put_string(buf, strlen(buf));
498: packet_send();
499: }
500: }
1.25 markus 501:
1.41 markus 502: /*
503: * This socket is listening for connections to a forwarded TCP/IP port.
504: */
505: void
506: channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
507: {
508: struct sockaddr addr;
509: int newsock, newch;
510: socklen_t addrlen;
511: char buf[1024], *remote_hostname;
512: int remote_port;
1.25 markus 513:
1.41 markus 514: if (FD_ISSET(c->sock, readset)) {
515: debug("Connection to port %d forwarding "
516: "to %.100s port %d requested.",
517: c->listening_port, c->path, c->host_port);
518: addrlen = sizeof(addr);
519: newsock = accept(c->sock, &addr, &addrlen);
520: if (newsock < 0) {
521: error("accept: %.100s", strerror(errno));
522: return;
523: }
524: remote_hostname = get_remote_hostname(newsock);
525: remote_port = get_peer_port(newsock);
526: snprintf(buf, sizeof buf,
527: "listen port %d for %.100s port %d, "
528: "connect from %.200s port %d",
529: c->listening_port, c->path, c->host_port,
530: remote_hostname, remote_port);
531: newch = channel_new("direct-tcpip",
532: SSH_CHANNEL_OPENING, newsock, newsock, -1,
533: c->local_window_max, c->local_maxpacket,
534: 0, xstrdup(buf));
1.44 markus 535: if (compat20) {
536: packet_start(SSH2_MSG_CHANNEL_OPEN);
537: packet_put_cstring("direct-tcpip");
538: packet_put_int(newch);
539: packet_put_int(c->local_window_max);
540: packet_put_int(c->local_maxpacket);
541: packet_put_string(c->path, strlen(c->path));
542: packet_put_int(c->host_port);
543: packet_put_cstring(remote_hostname);
544: packet_put_int(remote_port);
545: packet_send();
546: } else {
547: packet_start(SSH_MSG_PORT_OPEN);
548: packet_put_int(newch);
549: packet_put_string(c->path, strlen(c->path));
550: packet_put_int(c->host_port);
551: if (have_hostname_in_open) {
552: packet_put_string(buf, strlen(buf));
553: }
554: packet_send();
1.41 markus 555: }
556: xfree(remote_hostname);
557: }
558: }
1.25 markus 559:
1.41 markus 560: /*
561: * This is the authentication agent socket listening for connections from
562: * clients.
563: */
564: void
565: channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
566: {
567: struct sockaddr addr;
568: int newsock, newch;
569: socklen_t addrlen;
1.25 markus 570:
1.41 markus 571: if (FD_ISSET(c->sock, readset)) {
572: addrlen = sizeof(addr);
573: newsock = accept(c->sock, &addr, &addrlen);
574: if (newsock < 0) {
575: error("accept from auth socket: %.100s", strerror(errno));
576: return;
577: }
578: newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
579: xstrdup("accepted auth socket"));
580: packet_start(SSH_SMSG_AGENT_OPEN);
581: packet_put_int(newch);
582: packet_send();
583: }
584: }
1.25 markus 585:
1.41 markus 586: int
587: channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
588: {
589: char buf[16*1024];
590: int len;
1.25 markus 591:
1.41 markus 592: if (c->rfd != -1 &&
593: FD_ISSET(c->rfd, readset)) {
594: len = read(c->rfd, buf, sizeof(buf));
595: if (len <= 0) {
596: debug("channel %d: read<0 rfd %d len %d",
597: c->self, c->rfd, len);
1.25 markus 598: if (compat13) {
1.41 markus 599: buffer_consume(&c->output, buffer_len(&c->output));
600: c->type = SSH_CHANNEL_INPUT_DRAINING;
601: debug("Channel %d status set to input draining.", c->self);
1.25 markus 602: } else {
1.41 markus 603: chan_read_failed(c);
1.25 markus 604: }
1.41 markus 605: return -1;
606: }
607: buffer_append(&c->input, buf, len);
608: }
609: return 1;
610: }
611: int
612: channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
613: {
614: int len;
1.25 markus 615:
1.41 markus 616: /* Send buffered output data to the socket. */
617: if (c->wfd != -1 &&
618: FD_ISSET(c->wfd, writeset) &&
619: buffer_len(&c->output) > 0) {
620: len = write(c->wfd, buffer_ptr(&c->output),
621: buffer_len(&c->output));
622: if (len <= 0) {
623: if (compat13) {
624: buffer_consume(&c->output, buffer_len(&c->output));
625: debug("Channel %d status set to input draining.", c->self);
626: c->type = SSH_CHANNEL_INPUT_DRAINING;
627: } else {
628: chan_write_failed(c);
629: }
630: return -1;
1.25 markus 631: }
1.41 markus 632: buffer_consume(&c->output, len);
1.44 markus 633: if (compat20 && len > 0) {
634: c->local_consumed += len;
635: }
636: }
637: return 1;
638: }
639: int
640: channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
641: {
642: char buf[16*1024];
643: int len;
644:
1.45 ! markus 645: /** XXX handle drain efd, too */
1.44 markus 646: if (c->efd != -1) {
647: if (c->extended_usage == CHAN_EXTENDED_WRITE &&
648: FD_ISSET(c->efd, writeset) &&
649: buffer_len(&c->extended) > 0) {
650: len = write(c->efd, buffer_ptr(&c->extended),
651: buffer_len(&c->extended));
652: debug("channel %d: written %d to efd %d",
653: c->self, len, c->efd);
654: if (len > 0) {
655: buffer_consume(&c->extended, len);
656: c->local_consumed += len;
657: }
658: } else if (c->extended_usage == CHAN_EXTENDED_READ &&
659: FD_ISSET(c->efd, readset)) {
660: len = read(c->efd, buf, sizeof(buf));
661: debug("channel %d: read %d from efd %d",
662: c->self, len, c->efd);
1.45 ! markus 663: if (len == 0) {
! 664: debug("channel %d: closing efd %d",
! 665: c->self, c->efd);
! 666: close(c->efd);
! 667: c->efd = -1;
! 668: } else if (len > 0)
1.44 markus 669: buffer_append(&c->extended, buf, len);
670: }
671: }
672: return 1;
673: }
674: int
675: channel_check_window(Channel *c, fd_set * readset, fd_set * writeset)
676: {
677: if (!(c->flags & CHAN_CLOSE_SENT) &&
678: c->local_window < c->local_window_max/2 &&
679: c->local_consumed > 0) {
680: packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
681: packet_put_int(c->remote_id);
682: packet_put_int(c->local_consumed);
683: packet_send();
684: debug("channel %d: window %d sent adjust %d",
685: c->self, c->local_window,
686: c->local_consumed);
687: c->local_window += c->local_consumed;
688: c->local_consumed = 0;
1.1 deraadt 689: }
1.41 markus 690: return 1;
1.1 deraadt 691: }
692:
1.41 markus 693: void
694: channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
695: {
696: channel_handle_rfd(c, readset, writeset);
697: channel_handle_wfd(c, readset, writeset);
698: }
1.1 deraadt 699:
1.41 markus 700: void
1.44 markus 701: channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
702: {
703: channel_handle_rfd(c, readset, writeset);
704: channel_handle_wfd(c, readset, writeset);
705: channel_handle_efd(c, readset, writeset);
706: channel_check_window(c, readset, writeset);
707: }
708:
709: void
1.41 markus 710: channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1.1 deraadt 711: {
1.41 markus 712: int len;
713: /* Send buffered output data to the socket. */
714: if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
715: len = write(c->sock, buffer_ptr(&c->output),
716: buffer_len(&c->output));
717: if (len <= 0)
718: buffer_consume(&c->output, buffer_len(&c->output));
719: else
720: buffer_consume(&c->output, len);
721: }
722: }
1.25 markus 723:
1.41 markus 724: void
1.44 markus 725: channel_handler_init_20(void)
726: {
727: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
728: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
729:
730: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
731: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
732: }
733:
734: void
1.41 markus 735: channel_handler_init_13(void)
736: {
737: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
738: channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
739: channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
740: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
741: channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
742: channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
743: channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1.25 markus 744:
1.41 markus 745: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
746: channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
747: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
748: channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
749: channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
750: }
1.25 markus 751:
1.41 markus 752: void
753: channel_handler_init_15(void)
754: {
755: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
756: channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_15;
757: channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
758: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
759: channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1.25 markus 760:
1.41 markus 761: channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
762: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
763: channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
764: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
765: }
1.27 markus 766:
1.41 markus 767: void
768: channel_handler_init(void)
769: {
770: int i;
771: for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
772: channel_pre[i] = NULL;
773: channel_post[i] = NULL;
774: }
1.44 markus 775: if (compat20)
776: channel_handler_init_20();
777: else if (compat13)
1.41 markus 778: channel_handler_init_13();
779: else
780: channel_handler_init_15();
781: }
1.25 markus 782:
1.41 markus 783: void
784: channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
785: {
786: static int did_init = 0;
787: int i;
788: Channel *c;
1.25 markus 789:
1.41 markus 790: if (!did_init) {
791: channel_handler_init();
792: did_init = 1;
793: }
794: for (i = 0; i < channels_alloc; i++) {
795: c = &channels[i];
796: if (c->type == SSH_CHANNEL_FREE)
797: continue;
798: if (ftab[c->type] == NULL)
1.25 markus 799: continue;
1.41 markus 800: (*ftab[c->type])(c, readset, writeset);
1.44 markus 801: chan_delete_if_full_closed(c);
1.1 deraadt 802: }
803: }
804:
1.41 markus 805: void
806: channel_prepare_select(fd_set * readset, fd_set * writeset)
807: {
808: channel_handler(channel_pre, readset, writeset);
809: }
810:
811: void
812: channel_after_select(fd_set * readset, fd_set * writeset)
813: {
814: channel_handler(channel_post, readset, writeset);
815: }
816:
1.1 deraadt 817: /* If there is data to send to the connection, send some of it now. */
818:
1.25 markus 819: void
820: channel_output_poll()
1.1 deraadt 821: {
1.25 markus 822: int len, i;
1.41 markus 823: Channel *c;
1.1 deraadt 824:
1.25 markus 825: for (i = 0; i < channels_alloc; i++) {
1.41 markus 826: c = &channels[i];
1.37 markus 827:
1.27 markus 828: /* We are only interested in channels that can have buffered incoming data. */
1.37 markus 829: if (compat13) {
1.41 markus 830: if (c->type != SSH_CHANNEL_OPEN &&
831: c->type != SSH_CHANNEL_INPUT_DRAINING)
1.37 markus 832: continue;
833: } else {
1.41 markus 834: if (c->type != SSH_CHANNEL_OPEN)
1.37 markus 835: continue;
1.41 markus 836: if (c->istate != CHAN_INPUT_OPEN &&
837: c->istate != CHAN_INPUT_WAIT_DRAIN)
1.37 markus 838: continue;
839: }
1.44 markus 840: if (compat20 && (c->flags & CHAN_CLOSE_SENT)) {
841: debug("channel: %d: no data after CLOSE", c->self);
842: continue;
843: }
1.25 markus 844:
845: /* Get the amount of buffered data for this channel. */
1.41 markus 846: len = buffer_len(&c->input);
1.25 markus 847: if (len > 0) {
1.27 markus 848: /* Send some data for the other side over the secure connection. */
1.44 markus 849: if (compat20) {
850: if (len > c->remote_window)
851: len = c->remote_window;
852: if (len > c->remote_maxpacket)
853: len = c->remote_maxpacket;
1.25 markus 854: } else {
1.44 markus 855: if (packet_is_interactive()) {
856: if (len > 1024)
857: len = 512;
858: } else {
859: /* Keep the packets at reasonable size. */
860: if (len > packet_get_maxsize()/2)
861: len = packet_get_maxsize()/2;
862: }
1.25 markus 863: }
1.41 markus 864: if (len > 0) {
1.44 markus 865: packet_start(compat20 ?
866: SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1.41 markus 867: packet_put_int(c->remote_id);
868: packet_put_string(buffer_ptr(&c->input), len);
869: packet_send();
870: buffer_consume(&c->input, len);
871: c->remote_window -= len;
1.44 markus 872: debug("channel %d: send data len %d", c->self, len);
1.41 markus 873: }
874: } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1.25 markus 875: if (compat13)
876: fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1.27 markus 877: /*
878: * input-buffer is empty and read-socket shutdown:
879: * tell peer, that we will not send more data: send IEOF
880: */
1.41 markus 881: chan_ibuf_empty(c);
1.25 markus 882: }
1.44 markus 883: /* Send extended data, i.e. stderr */
884: if (compat20 &&
885: c->remote_window > 0 &&
886: (len = buffer_len(&c->extended)) > 0 &&
887: c->extended_usage == CHAN_EXTENDED_READ) {
888: if (len > c->remote_window)
889: len = c->remote_window;
890: if (len > c->remote_maxpacket)
891: len = c->remote_maxpacket;
892: packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
893: packet_put_int(c->remote_id);
894: packet_put_int(SSH2_EXTENDED_DATA_STDERR);
895: packet_put_string(buffer_ptr(&c->extended), len);
896: packet_send();
897: buffer_consume(&c->extended, len);
898: c->remote_window -= len;
899: }
1.25 markus 900: }
1.1 deraadt 901: }
902:
1.27 markus 903: /*
904: * This is called when a packet of type CHANNEL_DATA has just been received.
905: * The message type has already been consumed, but channel number and data is
906: * still there.
907: */
1.1 deraadt 908:
1.25 markus 909: void
1.41 markus 910: channel_input_data(int type, int plen)
1.1 deraadt 911: {
1.37 markus 912: int id;
1.25 markus 913: char *data;
914: unsigned int data_len;
1.41 markus 915: Channel *c;
1.25 markus 916:
917: /* Get the channel number and verify it. */
1.37 markus 918: id = packet_get_int();
1.41 markus 919: c = channel_lookup(id);
920: if (c == NULL)
1.37 markus 921: packet_disconnect("Received data for nonexistent channel %d.", id);
1.25 markus 922:
923: /* Ignore any data for non-open channels (might happen on close) */
1.41 markus 924: if (c->type != SSH_CHANNEL_OPEN &&
925: c->type != SSH_CHANNEL_X11_OPEN)
1.37 markus 926: return;
927:
928: /* same for protocol 1.5 if output end is no longer open */
1.41 markus 929: if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1.25 markus 930: return;
931:
932: /* Get the data. */
933: data = packet_get_string(&data_len);
1.41 markus 934:
1.44 markus 935: if (compat20){
936: if (data_len > c->local_maxpacket) {
937: log("channel %d: rcvd big packet %d, maxpack %d",
938: c->self, data_len, c->local_maxpacket);
939: }
940: if (data_len > c->local_window) {
941: log("channel %d: rcvd too much data %d, win %d",
942: c->self, data_len, c->local_window);
943: xfree(data);
944: return;
945: }
946: c->local_window -= data_len;
947: }else{
948: packet_integrity_check(plen, 4 + 4 + data_len, type);
949: }
1.41 markus 950: buffer_append(&c->output, data, data_len);
1.25 markus 951: xfree(data);
1.1 deraadt 952: }
1.44 markus 953: void
954: channel_input_extended_data(int type, int plen)
955: {
956: int id;
957: int tcode;
958: char *data;
959: unsigned int data_len;
960: Channel *c;
961:
962: /* Get the channel number and verify it. */
963: id = packet_get_int();
964: c = channel_lookup(id);
965:
966: if (c == NULL)
967: packet_disconnect("Received extended_data for bad channel %d.", id);
968: if (c->type != SSH_CHANNEL_OPEN) {
969: log("channel %d: ext data for non open", id);
970: return;
971: }
972: tcode = packet_get_int();
973: if (c->efd == -1 ||
974: c->extended_usage != CHAN_EXTENDED_WRITE ||
975: tcode != SSH2_EXTENDED_DATA_STDERR) {
976: log("channel %d: bad ext data", c->self);
977: return;
978: }
979: data = packet_get_string(&data_len);
980: if (data_len > c->local_window) {
981: log("channel %d: rcvd too much extended_data %d, win %d",
982: c->self, data_len, c->local_window);
983: xfree(data);
984: return;
985: }
986: debug("channel %d: rcvd ext data %d", c->self, data_len);
987: c->local_window -= data_len;
988: buffer_append(&c->extended, data, data_len);
989: xfree(data);
990: }
991:
1.1 deraadt 992:
1.27 markus 993: /*
994: * Returns true if no channel has too much buffered data, and false if one or
995: * more channel is overfull.
996: */
1.1 deraadt 997:
1.25 markus 998: int
999: channel_not_very_much_buffered_data()
1.1 deraadt 1000: {
1.25 markus 1001: unsigned int i;
1.41 markus 1002: Channel *c;
1.25 markus 1003:
1004: for (i = 0; i < channels_alloc; i++) {
1.41 markus 1005: c = &channels[i];
1006: if (c->type == SSH_CHANNEL_OPEN) {
1.44 markus 1007: if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
1.41 markus 1008: debug("channel %d: big input buffer %d",
1009: c->self, buffer_len(&c->input));
1.25 markus 1010: return 0;
1.41 markus 1011: }
1012: if (buffer_len(&c->output) > packet_get_maxsize()) {
1013: debug("channel %d: big output buffer %d",
1014: c->self, buffer_len(&c->output));
1.25 markus 1015: return 0;
1.41 markus 1016: }
1.25 markus 1017: }
1.1 deraadt 1018: }
1.25 markus 1019: return 1;
1.1 deraadt 1020: }
1021:
1.41 markus 1022: void
1023: channel_input_ieof(int type, int plen)
1024: {
1025: int id;
1026: Channel *c;
1027:
1028: packet_integrity_check(plen, 4, type);
1029:
1030: id = packet_get_int();
1031: c = channel_lookup(id);
1032: if (c == NULL)
1033: packet_disconnect("Received ieof for nonexistent channel %d.", id);
1034: chan_rcvd_ieof(c);
1035: }
1.1 deraadt 1036:
1.25 markus 1037: void
1.41 markus 1038: channel_input_close(int type, int plen)
1.1 deraadt 1039: {
1.41 markus 1040: int id;
1041: Channel *c;
1.1 deraadt 1042:
1.41 markus 1043: packet_integrity_check(plen, 4, type);
1044:
1045: id = packet_get_int();
1046: c = channel_lookup(id);
1047: if (c == NULL)
1048: packet_disconnect("Received close for nonexistent channel %d.", id);
1.27 markus 1049:
1050: /*
1051: * Send a confirmation that we have closed the channel and no more
1052: * data is coming for it.
1053: */
1.25 markus 1054: packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1.41 markus 1055: packet_put_int(c->remote_id);
1.25 markus 1056: packet_send();
1057:
1.27 markus 1058: /*
1059: * If the channel is in closed state, we have sent a close request,
1060: * and the other side will eventually respond with a confirmation.
1061: * Thus, we cannot free the channel here, because then there would be
1062: * no-one to receive the confirmation. The channel gets freed when
1063: * the confirmation arrives.
1064: */
1.41 markus 1065: if (c->type != SSH_CHANNEL_CLOSED) {
1.27 markus 1066: /*
1067: * Not a closed channel - mark it as draining, which will
1068: * cause it to be freed later.
1069: */
1.41 markus 1070: buffer_consume(&c->input, buffer_len(&c->input));
1071: c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1.25 markus 1072: }
1.1 deraadt 1073: }
1074:
1.41 markus 1075: /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1076: void
1077: channel_input_oclose(int type, int plen)
1078: {
1079: int id = packet_get_int();
1080: Channel *c = channel_lookup(id);
1081: packet_integrity_check(plen, 4, type);
1082: if (c == NULL)
1083: packet_disconnect("Received oclose for nonexistent channel %d.", id);
1084: chan_rcvd_oclose(c);
1085: }
1.1 deraadt 1086:
1.25 markus 1087: void
1.41 markus 1088: channel_input_close_confirmation(int type, int plen)
1.1 deraadt 1089: {
1.41 markus 1090: int id = packet_get_int();
1091: Channel *c = channel_lookup(id);
1.1 deraadt 1092:
1.41 markus 1093: if (c == NULL)
1094: packet_disconnect("Received close confirmation for "
1095: "out-of-range channel %d.", id);
1096: if (c->type != SSH_CHANNEL_CLOSED)
1097: packet_disconnect("Received close confirmation for "
1098: "non-closed channel %d (type %d).", id, c->type);
1099: channel_free(c->self);
1.1 deraadt 1100: }
1101:
1.25 markus 1102: void
1.41 markus 1103: channel_input_open_confirmation(int type, int plen)
1.1 deraadt 1104: {
1.41 markus 1105: int id, remote_id;
1106: Channel *c;
1.1 deraadt 1107:
1.44 markus 1108: if (!compat20)
1109: packet_integrity_check(plen, 4 + 4, type);
1.25 markus 1110:
1.41 markus 1111: id = packet_get_int();
1112: c = channel_lookup(id);
1.25 markus 1113:
1.41 markus 1114: if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1115: packet_disconnect("Received open confirmation for "
1116: "non-opening channel %d.", id);
1117: remote_id = packet_get_int();
1.27 markus 1118: /* Record the remote channel number and mark that the channel is now open. */
1.41 markus 1119: c->remote_id = remote_id;
1120: c->type = SSH_CHANNEL_OPEN;
1.44 markus 1121:
1122: if (compat20) {
1123: c->remote_window = packet_get_int();
1124: c->remote_maxpacket = packet_get_int();
1125: if (c->cb_fn != NULL && c->cb_event == type) {
1126: debug("callback start");
1127: c->cb_fn(c->self, c->cb_arg);
1128: debug("callback done");
1129: }
1130: debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1131: c->remote_window, c->remote_maxpacket);
1132: }
1.1 deraadt 1133: }
1134:
1.25 markus 1135: void
1.41 markus 1136: channel_input_open_failure(int type, int plen)
1.1 deraadt 1137: {
1.41 markus 1138: int id;
1139: Channel *c;
1140:
1.44 markus 1141: if (!compat20)
1142: packet_integrity_check(plen, 4, type);
1.41 markus 1143:
1144: id = packet_get_int();
1145: c = channel_lookup(id);
1.25 markus 1146:
1.41 markus 1147: if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1148: packet_disconnect("Received open failure for "
1149: "non-opening channel %d.", id);
1.44 markus 1150: if (compat20) {
1151: int reason = packet_get_int();
1152: char *msg = packet_get_string(NULL);
1153: log("channel_open_failure: %d: reason %d: %s", id, reason, msg);
1154: xfree(msg);
1155: }
1.25 markus 1156: /* Free the channel. This will also close the socket. */
1.41 markus 1157: channel_free(id);
1.1 deraadt 1158: }
1159:
1.44 markus 1160: void
1161: channel_input_channel_request(int type, int plen)
1162: {
1163: int id;
1164: Channel *c;
1165:
1166: id = packet_get_int();
1167: c = channel_lookup(id);
1168:
1169: if (c == NULL ||
1170: (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1171: packet_disconnect("Received request for "
1172: "non-open channel %d.", id);
1173: if (c->cb_fn != NULL && c->cb_event == type) {
1174: debug("callback start");
1175: c->cb_fn(c->self, c->cb_arg);
1176: debug("callback done");
1177: } else {
1178: char *service = packet_get_string(NULL);
1179: debug("channel: %d rcvd request for %s", c->self, service);
1180: debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1181: xfree(service);
1182: }
1183: }
1184:
1185: void
1186: channel_input_window_adjust(int type, int plen)
1187: {
1188: Channel *c;
1189: int id, adjust;
1190:
1191: if (!compat20)
1192: return;
1193:
1194: /* Get the channel number and verify it. */
1195: id = packet_get_int();
1196: c = channel_lookup(id);
1197:
1198: if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1199: log("Received window adjust for "
1200: "non-open channel %d.", id);
1201: return;
1202: }
1203: adjust = packet_get_int();
1204: debug("channel %d: rcvd adjust %d", id, adjust);
1205: c->remote_window += adjust;
1206: }
1207:
1.27 markus 1208: /*
1209: * Stops listening for channels, and removes any unix domain sockets that we
1210: * might have.
1211: */
1.1 deraadt 1212:
1.25 markus 1213: void
1214: channel_stop_listening()
1.1 deraadt 1215: {
1.25 markus 1216: int i;
1217: for (i = 0; i < channels_alloc; i++) {
1218: switch (channels[i].type) {
1219: case SSH_CHANNEL_AUTH_SOCKET:
1220: close(channels[i].sock);
1221: remove(channels[i].path);
1222: channel_free(i);
1223: break;
1224: case SSH_CHANNEL_PORT_LISTENER:
1225: case SSH_CHANNEL_X11_LISTENER:
1226: close(channels[i].sock);
1227: channel_free(i);
1228: break;
1229: default:
1230: break;
1231: }
1.1 deraadt 1232: }
1233: }
1234:
1.27 markus 1235: /*
1236: * Closes the sockets of all channels. This is used to close extra file
1237: * descriptors after a fork.
1238: */
1.1 deraadt 1239:
1.25 markus 1240: void
1241: channel_close_all()
1.1 deraadt 1242: {
1.25 markus 1243: int i;
1244: for (i = 0; i < channels_alloc; i++) {
1245: if (channels[i].type != SSH_CHANNEL_FREE)
1246: close(channels[i].sock);
1247: }
1.1 deraadt 1248: }
1249:
1250: /* Returns the maximum file descriptor number used by the channels. */
1251:
1.25 markus 1252: int
1253: channel_max_fd()
1.1 deraadt 1254: {
1.25 markus 1255: return channel_max_fd_value;
1.1 deraadt 1256: }
1257:
1258: /* Returns true if any channel is still open. */
1259:
1.25 markus 1260: int
1261: channel_still_open()
1.1 deraadt 1262: {
1.25 markus 1263: unsigned int i;
1264: for (i = 0; i < channels_alloc; i++)
1265: switch (channels[i].type) {
1266: case SSH_CHANNEL_FREE:
1267: case SSH_CHANNEL_X11_LISTENER:
1268: case SSH_CHANNEL_PORT_LISTENER:
1269: case SSH_CHANNEL_CLOSED:
1270: case SSH_CHANNEL_AUTH_SOCKET:
1271: continue;
1.44 markus 1272: case SSH_CHANNEL_LARVAL:
1273: if (!compat20)
1274: fatal("cannot happen: SSH_CHANNEL_LARVAL");
1275: continue;
1.25 markus 1276: case SSH_CHANNEL_OPENING:
1277: case SSH_CHANNEL_OPEN:
1278: case SSH_CHANNEL_X11_OPEN:
1279: return 1;
1280: case SSH_CHANNEL_INPUT_DRAINING:
1281: case SSH_CHANNEL_OUTPUT_DRAINING:
1282: if (!compat13)
1283: fatal("cannot happen: OUT_DRAIN");
1284: return 1;
1285: default:
1286: fatal("channel_still_open: bad channel type %d", channels[i].type);
1287: /* NOTREACHED */
1288: }
1289: return 0;
1.1 deraadt 1290: }
1291:
1.27 markus 1292: /*
1293: * Returns a message describing the currently open forwarded connections,
1294: * suitable for sending to the client. The message contains crlf pairs for
1295: * newlines.
1296: */
1.1 deraadt 1297:
1.25 markus 1298: char *
1299: channel_open_message()
1.1 deraadt 1300: {
1.25 markus 1301: Buffer buffer;
1302: int i;
1303: char buf[512], *cp;
1304:
1305: buffer_init(&buffer);
1306: snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1.1 deraadt 1307: buffer_append(&buffer, buf, strlen(buf));
1.25 markus 1308: for (i = 0; i < channels_alloc; i++) {
1309: Channel *c = &channels[i];
1310: switch (c->type) {
1311: case SSH_CHANNEL_FREE:
1312: case SSH_CHANNEL_X11_LISTENER:
1313: case SSH_CHANNEL_PORT_LISTENER:
1314: case SSH_CHANNEL_CLOSED:
1315: case SSH_CHANNEL_AUTH_SOCKET:
1316: continue;
1.44 markus 1317: case SSH_CHANNEL_LARVAL:
1.25 markus 1318: case SSH_CHANNEL_OPENING:
1319: case SSH_CHANNEL_OPEN:
1320: case SSH_CHANNEL_X11_OPEN:
1321: case SSH_CHANNEL_INPUT_DRAINING:
1322: case SSH_CHANNEL_OUTPUT_DRAINING:
1.41 markus 1323: snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1.37 markus 1324: c->self, c->remote_name,
1325: c->type, c->remote_id,
1326: c->istate, buffer_len(&c->input),
1.41 markus 1327: c->ostate, buffer_len(&c->output),
1328: c->rfd, c->wfd);
1.25 markus 1329: buffer_append(&buffer, buf, strlen(buf));
1330: continue;
1331: default:
1.41 markus 1332: fatal("channel_open_message: bad channel type %d", c->type);
1.25 markus 1333: /* NOTREACHED */
1334: }
1335: }
1336: buffer_append(&buffer, "\0", 1);
1337: cp = xstrdup(buffer_ptr(&buffer));
1338: buffer_free(&buffer);
1339: return cp;
1.1 deraadt 1340: }
1341:
1.27 markus 1342: /*
1343: * Initiate forwarding of connections to local port "port" through the secure
1344: * channel to host:port from remote side.
1345: */
1.1 deraadt 1346:
1.25 markus 1347: void
1.31 markus 1348: channel_request_local_forwarding(u_short port, const char *host,
1.33 markus 1349: u_short host_port, int gateway_ports)
1.25 markus 1350: {
1.35 markus 1351: int success, ch, sock, on = 1;
1352: struct addrinfo hints, *ai, *aitop;
1353: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.28 markus 1354: struct linger linger;
1.25 markus 1355:
1356: if (strlen(host) > sizeof(channels[0].path) - 1)
1357: packet_disconnect("Forward host name too long.");
1358:
1.28 markus 1359: /*
1.35 markus 1360: * getaddrinfo returns a loopback address if the hostname is
1361: * set to NULL and hints.ai_flags is not AI_PASSIVE
1.28 markus 1362: */
1.35 markus 1363: memset(&hints, 0, sizeof(hints));
1364: hints.ai_family = IPv4or6;
1365: hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1366: hints.ai_socktype = SOCK_STREAM;
1367: snprintf(strport, sizeof strport, "%d", port);
1368: if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1369: packet_disconnect("getaddrinfo: fatal error");
1370:
1371: success = 0;
1372: for (ai = aitop; ai; ai = ai->ai_next) {
1373: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1374: continue;
1375: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1376: strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1377: error("channel_request_local_forwarding: getnameinfo failed");
1378: continue;
1379: }
1380: /* Create a port to listen for the host. */
1381: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1382: if (sock < 0) {
1383: /* this is no error since kernel may not support ipv6 */
1384: verbose("socket: %.100s", strerror(errno));
1385: continue;
1386: }
1387: /*
1388: * Set socket options. We would like the socket to disappear
1389: * as soon as it has been closed for whatever reason.
1390: */
1391: setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1392: linger.l_onoff = 1;
1393: linger.l_linger = 5;
1394: setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1395: debug("Local forwarding listening on %s port %s.", ntop, strport);
1396:
1397: /* Bind the socket to the address. */
1398: if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1399: /* address can be in use ipv6 address is already bound */
1400: verbose("bind: %.100s", strerror(errno));
1401: close(sock);
1402: continue;
1403: }
1404: /* Start listening for connections on the socket. */
1405: if (listen(sock, 5) < 0) {
1406: error("listen: %.100s", strerror(errno));
1407: close(sock);
1408: continue;
1409: }
1410: /* Allocate a channel number for the socket. */
1.41 markus 1411: ch = channel_new(
1412: "port listener", SSH_CHANNEL_PORT_LISTENER,
1413: sock, sock, -1,
1414: CHAN_WINDOW_DEFAULT, CHAN_PACKET_DEFAULT,
1415: 0, xstrdup("port listener"));
1.35 markus 1416: strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
1417: channels[ch].host_port = host_port;
1418: channels[ch].listening_port = port;
1419: success = 1;
1420: }
1421: if (success == 0)
1422: packet_disconnect("cannot listen port: %d", port);
1423: freeaddrinfo(aitop);
1.25 markus 1424: }
1.1 deraadt 1425:
1.27 markus 1426: /*
1427: * Initiate forwarding of connections to port "port" on remote host through
1428: * the secure channel to host:port from local side.
1429: */
1.1 deraadt 1430:
1.25 markus 1431: void
1.41 markus 1432: channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect,
1433: u_short port_to_connect)
1.25 markus 1434: {
1435: int payload_len;
1436: /* Record locally that connection to this host/port is permitted. */
1437: if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1438: fatal("channel_request_remote_forwarding: too many forwards");
1439:
1.41 markus 1440: permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
1441: permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
1442: permitted_opens[num_permitted_opens].listen_port = listen_port;
1.25 markus 1443: num_permitted_opens++;
1444:
1445: /* Send the forward request to the remote side. */
1.44 markus 1446: if (compat20) {
1447: const char *address_to_bind = "0.0.0.0";
1448: packet_start(SSH2_MSG_GLOBAL_REQUEST);
1449: packet_put_cstring("tcpip-forward");
1450: packet_put_char(0); /* boolean: want reply */
1451: packet_put_cstring(address_to_bind);
1452: packet_put_int(listen_port);
1453: } else {
1454: packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
1455: packet_put_int(port_to_connect);
1456: packet_put_cstring(host_to_connect);
1457: packet_put_int(listen_port);
1458: packet_send();
1459: packet_write_wait();
1460: /*
1461: * Wait for response from the remote side. It will send a disconnect
1462: * message on failure, and we will never see it here.
1463: */
1464: packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
1465: }
1.1 deraadt 1466: }
1467:
1.27 markus 1468: /*
1469: * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1470: * listening for the port, and sends back a success reply (or disconnect
1471: * message if there was an error). This never returns if there was an error.
1472: */
1.1 deraadt 1473:
1.25 markus 1474: void
1475: channel_input_port_forward_request(int is_root)
1.1 deraadt 1476: {
1.31 markus 1477: u_short port, host_port;
1.25 markus 1478: char *hostname;
1.1 deraadt 1479:
1.25 markus 1480: /* Get arguments from the packet. */
1481: port = packet_get_int();
1482: hostname = packet_get_string(NULL);
1483: host_port = packet_get_int();
1484:
1.27 markus 1485: /*
1486: * Check that an unprivileged user is not trying to forward a
1487: * privileged port.
1488: */
1.25 markus 1489: if (port < IPPORT_RESERVED && !is_root)
1490: packet_disconnect("Requested forwarding of port %d but user is not root.",
1491: port);
1.33 markus 1492: /*
1493: * Initiate forwarding,
1494: * bind port to localhost only (gateway ports == 0).
1495: */
1496: channel_request_local_forwarding(port, hostname, host_port, 0);
1.25 markus 1497:
1498: /* Free the argument string. */
1499: xfree(hostname);
1.1 deraadt 1500: }
1501:
1.41 markus 1502: /* XXX move to aux.c */
1503: int
1504: channel_connect_to(const char *host, u_short host_port)
1505: {
1506: struct addrinfo hints, *ai, *aitop;
1507: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1508: int gaierr;
1509: int sock = -1;
1510:
1511: memset(&hints, 0, sizeof(hints));
1512: hints.ai_family = IPv4or6;
1513: hints.ai_socktype = SOCK_STREAM;
1514: snprintf(strport, sizeof strport, "%d", host_port);
1515: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
1516: error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
1517: return -1;
1518: }
1519: for (ai = aitop; ai; ai = ai->ai_next) {
1520: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1521: continue;
1522: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1523: strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1524: error("channel_connect_to: getnameinfo failed");
1525: continue;
1526: }
1527: /* Create the socket. */
1528: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1529: if (sock < 0) {
1530: error("socket: %.100s", strerror(errno));
1531: continue;
1532: }
1533: /* Connect to the host/port. */
1534: if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1535: error("connect %.100s port %s: %.100s", ntop, strport,
1536: strerror(errno));
1537: close(sock);
1538: continue; /* fail -- try next */
1539: }
1540: break; /* success */
1541:
1542: }
1543: freeaddrinfo(aitop);
1544: if (!ai) {
1545: error("connect %.100s port %d: failed.", host, host_port);
1546: return -1;
1547: }
1548: /* success */
1549: return sock;
1550: }
1.27 markus 1551: /*
1552: * This is called after receiving PORT_OPEN message. This attempts to
1553: * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
1554: * or CHANNEL_OPEN_FAILURE.
1555: */
1.1 deraadt 1556:
1.25 markus 1557: void
1.41 markus 1558: channel_input_port_open(int type, int plen)
1.1 deraadt 1559: {
1.31 markus 1560: u_short host_port;
1.25 markus 1561: char *host, *originator_string;
1.41 markus 1562: int remote_channel, sock = -1, newch, i, denied;
1.39 markus 1563: unsigned int host_len, originator_len;
1.25 markus 1564:
1565: /* Get remote channel number. */
1566: remote_channel = packet_get_int();
1567:
1568: /* Get host name to connect to. */
1569: host = packet_get_string(&host_len);
1570:
1571: /* Get port to connect to. */
1572: host_port = packet_get_int();
1573:
1574: /* Get remote originator name. */
1.29 markus 1575: if (have_hostname_in_open) {
1.25 markus 1576: originator_string = packet_get_string(&originator_len);
1.29 markus 1577: originator_len += 4; /* size of packet_int */
1578: } else {
1.25 markus 1579: originator_string = xstrdup("unknown (remote did not supply name)");
1.29 markus 1580: originator_len = 0; /* no originator supplied */
1581: }
1.25 markus 1582:
1.41 markus 1583: packet_integrity_check(plen,
1584: 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
1.25 markus 1585:
1586: /* Check if opening that port is permitted. */
1.41 markus 1587: denied = 0;
1.25 markus 1588: if (!all_opens_permitted) {
1589: /* Go trough all permitted ports. */
1590: for (i = 0; i < num_permitted_opens; i++)
1.41 markus 1591: if (permitted_opens[i].port_to_connect == host_port &&
1592: strcmp(permitted_opens[i].host_to_connect, host) == 0)
1.25 markus 1593: break;
1594:
1595: /* Check if we found the requested port among those permitted. */
1596: if (i >= num_permitted_opens) {
1597: /* The port is not permitted. */
1598: log("Received request to connect to %.100s:%d, but the request was denied.",
1599: host, host_port);
1.41 markus 1600: denied = 1;
1.25 markus 1601: }
1602: }
1.41 markus 1603: sock = denied ? -1 : channel_connect_to(host, host_port);
1604: if (sock > 0) {
1605: /* Allocate a channel for this connection. */
1606: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
1607: channels[newch].remote_id = remote_channel;
1608:
1609: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1610: packet_put_int(remote_channel);
1611: packet_put_int(newch);
1612: packet_send();
1613: } else {
1614: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1615: packet_put_int(remote_channel);
1616: packet_send();
1.25 markus 1617: }
1618: xfree(host);
1.1 deraadt 1619: }
1620:
1.27 markus 1621: /*
1622: * Creates an internet domain socket for listening for X11 connections.
1623: * Returns a suitable value for the DISPLAY variable, or NULL if an error
1624: * occurs.
1625: */
1.1 deraadt 1626:
1.35 markus 1627: #define NUM_SOCKS 10
1628:
1.25 markus 1629: char *
1.33 markus 1630: x11_create_display_inet(int screen_number, int x11_display_offset)
1.1 deraadt 1631: {
1.31 markus 1632: int display_number, sock;
1633: u_short port;
1.35 markus 1634: struct addrinfo hints, *ai, *aitop;
1635: char strport[NI_MAXSERV];
1636: int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
1637: char display[512];
1.25 markus 1638: char hostname[MAXHOSTNAMELEN];
1639:
1.33 markus 1640: for (display_number = x11_display_offset;
1.25 markus 1641: display_number < MAX_DISPLAYS;
1642: display_number++) {
1643: port = 6000 + display_number;
1.35 markus 1644: memset(&hints, 0, sizeof(hints));
1645: hints.ai_family = IPv4or6;
1.36 markus 1646: hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
1.35 markus 1647: hints.ai_socktype = SOCK_STREAM;
1648: snprintf(strport, sizeof strport, "%d", port);
1649: if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
1650: error("getaddrinfo: %.100s", gai_strerror(gaierr));
1.25 markus 1651: return NULL;
1652: }
1.35 markus 1653: for (ai = aitop; ai; ai = ai->ai_next) {
1654: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1655: continue;
1656: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1657: if (sock < 0) {
1658: error("socket: %.100s", strerror(errno));
1659: return NULL;
1660: }
1661: if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1662: debug("bind port %d: %.100s", port, strerror(errno));
1663: shutdown(sock, SHUT_RDWR);
1664: close(sock);
1665: for (n = 0; n < num_socks; n++) {
1666: shutdown(socks[n], SHUT_RDWR);
1667: close(socks[n]);
1668: }
1669: num_socks = 0;
1670: break;
1671: }
1672: socks[num_socks++] = sock;
1673: if (num_socks == NUM_SOCKS)
1674: break;
1.25 markus 1675: }
1.35 markus 1676: if (num_socks > 0)
1677: break;
1.25 markus 1678: }
1679: if (display_number >= MAX_DISPLAYS) {
1680: error("Failed to allocate internet-domain X11 display socket.");
1681: return NULL;
1682: }
1683: /* Start listening for connections on the socket. */
1.35 markus 1684: for (n = 0; n < num_socks; n++) {
1685: sock = socks[n];
1686: if (listen(sock, 5) < 0) {
1687: error("listen: %.100s", strerror(errno));
1688: shutdown(sock, SHUT_RDWR);
1689: close(sock);
1690: return NULL;
1691: }
1.25 markus 1692: }
1.35 markus 1693:
1.25 markus 1694: /* Set up a suitable value for the DISPLAY variable. */
1695: if (gethostname(hostname, sizeof(hostname)) < 0)
1696: fatal("gethostname: %.100s", strerror(errno));
1.35 markus 1697: snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1.25 markus 1698: display_number, screen_number);
1699:
1.35 markus 1700: /* Allocate a channel for each socket. */
1701: for (n = 0; n < num_socks; n++) {
1702: sock = socks[n];
1703: (void) channel_allocate(SSH_CHANNEL_X11_LISTENER, sock,
1704: xstrdup("X11 inet listener"));
1705: }
1.1 deraadt 1706:
1.25 markus 1707: /* Return a suitable value for the DISPLAY environment variable. */
1.35 markus 1708: return xstrdup(display);
1.1 deraadt 1709: }
1710:
1711: #ifndef X_UNIX_PATH
1712: #define X_UNIX_PATH "/tmp/.X11-unix/X"
1713: #endif
1714:
1715: static
1716: int
1.30 deraadt 1717: connect_local_xsocket(unsigned int dnr)
1.1 deraadt 1718: {
1.25 markus 1719: static const char *const x_sockets[] = {
1720: X_UNIX_PATH "%u",
1721: "/var/X/.X11-unix/X" "%u",
1722: "/usr/spool/sockets/X11/" "%u",
1723: NULL
1724: };
1725: int sock;
1726: struct sockaddr_un addr;
1727: const char *const * path;
1728:
1729: for (path = x_sockets; *path; ++path) {
1730: sock = socket(AF_UNIX, SOCK_STREAM, 0);
1731: if (sock < 0)
1732: error("socket: %.100s", strerror(errno));
1733: memset(&addr, 0, sizeof(addr));
1734: addr.sun_family = AF_UNIX;
1735: snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
1736: if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
1737: return sock;
1738: close(sock);
1739: }
1740: error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
1741: return -1;
1.1 deraadt 1742: }
1743:
1744:
1.27 markus 1745: /*
1746: * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
1747: * the remote channel number. We should do whatever we want, and respond
1748: * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
1749: */
1.1 deraadt 1750:
1.25 markus 1751: void
1.41 markus 1752: x11_input_open(int type, int plen)
1.1 deraadt 1753: {
1.35 markus 1754: int remote_channel, display_number, sock = 0, newch;
1.25 markus 1755: const char *display;
1756: char buf[1024], *cp, *remote_host;
1.39 markus 1757: unsigned int remote_len;
1.35 markus 1758: struct addrinfo hints, *ai, *aitop;
1759: char strport[NI_MAXSERV];
1760: int gaierr;
1.25 markus 1761:
1762: /* Get remote channel number. */
1763: remote_channel = packet_get_int();
1764:
1765: /* Get remote originator name. */
1.29 markus 1766: if (have_hostname_in_open) {
1.25 markus 1767: remote_host = packet_get_string(&remote_len);
1.29 markus 1768: remote_len += 4;
1769: } else {
1.25 markus 1770: remote_host = xstrdup("unknown (remote did not supply name)");
1.29 markus 1771: remote_len = 0;
1772: }
1.25 markus 1773:
1774: debug("Received X11 open request.");
1.41 markus 1775: packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
1.25 markus 1776:
1777: /* Try to open a socket for the local X server. */
1778: display = getenv("DISPLAY");
1779: if (!display) {
1780: error("DISPLAY not set.");
1781: goto fail;
1782: }
1.27 markus 1783: /*
1784: * Now we decode the value of the DISPLAY variable and make a
1785: * connection to the real X server.
1786: */
1787:
1788: /*
1789: * Check if it is a unix domain socket. Unix domain displays are in
1790: * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
1791: */
1.25 markus 1792: if (strncmp(display, "unix:", 5) == 0 ||
1793: display[0] == ':') {
1794: /* Connect to the unix domain socket. */
1795: if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
1796: error("Could not parse display number from DISPLAY: %.100s",
1797: display);
1798: goto fail;
1799: }
1800: /* Create a socket. */
1801: sock = connect_local_xsocket(display_number);
1802: if (sock < 0)
1803: goto fail;
1804:
1805: /* OK, we now have a connection to the display. */
1806: goto success;
1807: }
1.27 markus 1808: /*
1809: * Connect to an inet socket. The DISPLAY value is supposedly
1810: * hostname:d[.s], where hostname may also be numeric IP address.
1811: */
1.25 markus 1812: strncpy(buf, display, sizeof(buf));
1813: buf[sizeof(buf) - 1] = 0;
1814: cp = strchr(buf, ':');
1815: if (!cp) {
1816: error("Could not find ':' in DISPLAY: %.100s", display);
1817: goto fail;
1818: }
1819: *cp = 0;
1.27 markus 1820: /* buf now contains the host name. But first we parse the display number. */
1.25 markus 1821: if (sscanf(cp + 1, "%d", &display_number) != 1) {
1822: error("Could not parse display number from DISPLAY: %.100s",
1823: display);
1824: goto fail;
1825: }
1.35 markus 1826:
1827: /* Look up the host address */
1828: memset(&hints, 0, sizeof(hints));
1829: hints.ai_family = IPv4or6;
1830: hints.ai_socktype = SOCK_STREAM;
1831: snprintf(strport, sizeof strport, "%d", 6000 + display_number);
1832: if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
1833: error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
1.25 markus 1834: goto fail;
1835: }
1.35 markus 1836: for (ai = aitop; ai; ai = ai->ai_next) {
1837: /* Create a socket. */
1838: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1839: if (sock < 0) {
1840: debug("socket: %.100s", strerror(errno));
1.41 markus 1841: continue;
1842: }
1843: /* Connect it to the display. */
1844: if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1845: debug("connect %.100s port %d: %.100s", buf,
1846: 6000 + display_number, strerror(errno));
1847: close(sock);
1848: continue;
1849: }
1850: /* Success */
1851: break;
1.35 markus 1852: }
1853: freeaddrinfo(aitop);
1854: if (!ai) {
1855: error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
1856: strerror(errno));
1.25 markus 1857: goto fail;
1858: }
1859: success:
1860: /* We have successfully obtained a connection to the real X display. */
1861:
1862: /* Allocate a channel for this connection. */
1863: if (x11_saved_proto == NULL)
1864: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, remote_host);
1865: else
1866: newch = channel_allocate(SSH_CHANNEL_X11_OPEN, sock, remote_host);
1867: channels[newch].remote_id = remote_channel;
1868:
1869: /* Send a confirmation to the remote host. */
1870: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1871: packet_put_int(remote_channel);
1872: packet_put_int(newch);
1873: packet_send();
1874:
1875: return;
1876:
1877: fail:
1878: /* Send refusal to the remote host. */
1879: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1880: packet_put_int(remote_channel);
1881: packet_send();
1.1 deraadt 1882: }
1883:
1.27 markus 1884: /*
1885: * Requests forwarding of X11 connections, generates fake authentication
1886: * data, and enables authentication spoofing.
1887: */
1.1 deraadt 1888:
1.25 markus 1889: void
1890: x11_request_forwarding_with_spoofing(const char *proto, const char *data)
1.1 deraadt 1891: {
1.25 markus 1892: unsigned int data_len = (unsigned int) strlen(data) / 2;
1893: unsigned int i, value;
1894: char *new_data;
1895: int screen_number;
1896: const char *cp;
1897: u_int32_t rand = 0;
1898:
1899: cp = getenv("DISPLAY");
1900: if (cp)
1901: cp = strchr(cp, ':');
1902: if (cp)
1903: cp = strchr(cp, '.');
1904: if (cp)
1905: screen_number = atoi(cp + 1);
1906: else
1907: screen_number = 0;
1908:
1909: /* Save protocol name. */
1910: x11_saved_proto = xstrdup(proto);
1911:
1.27 markus 1912: /*
1913: * Extract real authentication data and generate fake data of the
1914: * same length.
1915: */
1.25 markus 1916: x11_saved_data = xmalloc(data_len);
1917: x11_fake_data = xmalloc(data_len);
1918: for (i = 0; i < data_len; i++) {
1919: if (sscanf(data + 2 * i, "%2x", &value) != 1)
1920: fatal("x11_request_forwarding: bad authentication data: %.100s", data);
1921: if (i % 4 == 0)
1922: rand = arc4random();
1923: x11_saved_data[i] = value;
1924: x11_fake_data[i] = rand & 0xff;
1925: rand >>= 8;
1926: }
1927: x11_saved_data_len = data_len;
1928: x11_fake_data_len = data_len;
1929:
1930: /* Convert the fake data into hex. */
1931: new_data = xmalloc(2 * data_len + 1);
1932: for (i = 0; i < data_len; i++)
1933: sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]);
1934:
1935: /* Send the request packet. */
1936: packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
1937: packet_put_string(proto, strlen(proto));
1938: packet_put_string(new_data, strlen(new_data));
1939: packet_put_int(screen_number);
1940: packet_send();
1941: packet_write_wait();
1942: xfree(new_data);
1.1 deraadt 1943: }
1944:
1945: /* Sends a message to the server to request authentication fd forwarding. */
1946:
1.25 markus 1947: void
1948: auth_request_forwarding()
1.1 deraadt 1949: {
1.25 markus 1950: packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
1951: packet_send();
1952: packet_write_wait();
1.1 deraadt 1953: }
1954:
1.27 markus 1955: /*
1956: * Returns the name of the forwarded authentication socket. Returns NULL if
1957: * there is no forwarded authentication socket. The returned value points to
1958: * a static buffer.
1959: */
1.1 deraadt 1960:
1.25 markus 1961: char *
1962: auth_get_socket_name()
1.1 deraadt 1963: {
1.25 markus 1964: return channel_forwarded_auth_socket_name;
1.1 deraadt 1965: }
1966:
1.12 markus 1967: /* removes the agent forwarding socket */
1968:
1.25 markus 1969: void
1970: cleanup_socket(void)
1971: {
1972: remove(channel_forwarded_auth_socket_name);
1973: rmdir(channel_forwarded_auth_socket_dir);
1.12 markus 1974: }
1975:
1.27 markus 1976: /*
1977: * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
1978: * This starts forwarding authentication requests.
1979: */
1.1 deraadt 1980:
1.25 markus 1981: void
1982: auth_input_request_forwarding(struct passwd * pw)
1.1 deraadt 1983: {
1.25 markus 1984: int sock, newch;
1985: struct sockaddr_un sunaddr;
1986:
1987: if (auth_get_socket_name() != NULL)
1988: fatal("Protocol error: authentication forwarding requested twice.");
1989:
1990: /* Temporarily drop privileged uid for mkdir/bind. */
1991: temporarily_use_uid(pw->pw_uid);
1992:
1993: /* Allocate a buffer for the socket name, and format the name. */
1994: channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
1995: channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
1996: strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
1997:
1998: /* Create private directory for socket */
1999: if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL)
2000: packet_disconnect("mkdtemp: %.100s", strerror(errno));
2001: snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
2002: channel_forwarded_auth_socket_dir, (int) getpid());
2003:
2004: if (atexit(cleanup_socket) < 0) {
2005: int saved = errno;
2006: cleanup_socket();
2007: packet_disconnect("socket: %.100s", strerror(saved));
2008: }
2009: /* Create the socket. */
2010: sock = socket(AF_UNIX, SOCK_STREAM, 0);
2011: if (sock < 0)
2012: packet_disconnect("socket: %.100s", strerror(errno));
2013:
2014: /* Bind it to the name. */
2015: memset(&sunaddr, 0, sizeof(sunaddr));
2016: sunaddr.sun_family = AF_UNIX;
2017: strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
2018: sizeof(sunaddr.sun_path));
2019:
2020: if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2021: packet_disconnect("bind: %.100s", strerror(errno));
2022:
2023: /* Restore the privileged uid. */
2024: restore_uid();
2025:
2026: /* Start listening on the socket. */
2027: if (listen(sock, 5) < 0)
2028: packet_disconnect("listen: %.100s", strerror(errno));
2029:
2030: /* Allocate a channel for the authentication agent socket. */
2031: newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock,
2032: xstrdup("auth socket"));
1.32 deraadt 2033: strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
2034: sizeof(channels[newch].path));
1.1 deraadt 2035: }
2036:
2037: /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2038:
1.25 markus 2039: void
1.41 markus 2040: auth_input_open_request(int type, int plen)
1.1 deraadt 2041: {
1.25 markus 2042: int remch, sock, newch;
2043: char *dummyname;
1.41 markus 2044:
2045: packet_integrity_check(plen, 4, type);
1.25 markus 2046:
2047: /* Read the remote channel number from the message. */
2048: remch = packet_get_int();
2049:
1.27 markus 2050: /*
2051: * Get a connection to the local authentication agent (this may again
2052: * get forwarded).
2053: */
1.25 markus 2054: sock = ssh_get_authentication_socket();
2055:
1.27 markus 2056: /*
2057: * If we could not connect the agent, send an error message back to
2058: * the server. This should never happen unless the agent dies,
2059: * because authentication forwarding is only enabled if we have an
2060: * agent.
2061: */
1.25 markus 2062: if (sock < 0) {
2063: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2064: packet_put_int(remch);
2065: packet_send();
2066: return;
2067: }
2068: debug("Forwarding authentication connection.");
1.1 deraadt 2069:
1.27 markus 2070: /*
2071: * Dummy host name. This will be freed when the channel is freed; it
2072: * will still be valid in the packet_put_string below since the
2073: * channel cannot yet be freed at that point.
2074: */
1.25 markus 2075: dummyname = xstrdup("authentication agent connection");
2076:
2077: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
2078: channels[newch].remote_id = remch;
2079:
2080: /* Send a confirmation to the remote host. */
2081: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2082: packet_put_int(remch);
2083: packet_put_int(newch);
1.44 markus 2084: packet_send();
2085: }
2086:
2087: void
2088: channel_open(int id)
2089: {
2090: Channel *c = channel_lookup(id);
2091: if (c == NULL) {
2092: log("channel_open: %d: bad id", id);
2093: return;
2094: }
2095: packet_start(SSH2_MSG_CHANNEL_OPEN);
2096: packet_put_cstring(c->ctype);
2097: packet_put_int(c->self);
2098: packet_put_int(c->local_window);
2099: packet_put_int(c->local_maxpacket);
2100: packet_send();
2101: debug("channel open %d", id);
2102: }
2103: void
2104: channel_request(int id, char *service, int wantconfirm)
2105: {
2106: channel_request_start(id, service, wantconfirm);
2107: packet_send();
2108: debug("channel request %d: %s", id, service) ;
2109: }
2110: void
2111: channel_request_start(int id, char *service, int wantconfirm)
2112: {
2113: Channel *c = channel_lookup(id);
2114: if (c == NULL) {
2115: log("channel_request: %d: bad id", id);
2116: return;
2117: }
2118: packet_start(SSH2_MSG_CHANNEL_REQUEST);
2119: packet_put_int(c->remote_id);
2120: packet_put_cstring(service);
2121: packet_put_char(wantconfirm);
2122: }
2123: void
2124: channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
2125: {
2126: Channel *c = channel_lookup(id);
2127: if (c == NULL) {
2128: log("channel_register_callback: %d: bad id", id);
2129: return;
2130: }
2131: c->cb_event = mtype;
2132: c->cb_fn = fn;
2133: c->cb_arg = arg;
2134: }
2135: void
2136: channel_register_cleanup(int id, channel_callback_fn *fn)
2137: {
2138: Channel *c = channel_lookup(id);
2139: if (c == NULL) {
2140: log("channel_register_cleanup: %d: bad id", id);
2141: return;
2142: }
2143: c->dettach_user = fn;
2144: }
2145: void
2146: channel_cancel_cleanup(int id)
2147: {
2148: Channel *c = channel_lookup(id);
2149: if (c == NULL) {
2150: log("channel_cancel_cleanup: %d: bad id", id);
2151: return;
2152: }
2153: c->dettach_user = NULL;
2154: }
2155:
2156: void
2157: channel_set_fds(int id, int rfd, int wfd, int efd, int extusage)
2158: {
2159: Channel *c = channel_lookup(id);
2160: if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
2161: fatal("channel_activate for non-larval channel %d.", id);
2162: if (rfd > channel_max_fd_value)
2163: channel_max_fd_value = rfd;
2164: if (wfd > channel_max_fd_value)
2165: channel_max_fd_value = wfd;
2166: if (efd > channel_max_fd_value)
2167: channel_max_fd_value = efd;
2168: c->type = SSH_CHANNEL_OPEN;
2169: c->rfd = rfd;
2170: c->wfd = wfd;
2171: c->efd = efd;
2172: c->extended_usage = extusage;
2173: /* XXX window size? */
2174: c->local_window = c->local_window_max = c->local_maxpacket/2;
2175: packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2176: packet_put_int(c->remote_id);
2177: packet_put_int(c->local_window);
1.25 markus 2178: packet_send();
1.1 deraadt 2179: }
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