Annotation of src/usr.bin/ssh/channels.c, Revision 1.44
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"
1.44 ! markus 20: RCSID("$Id: channels.c,v 1.43 2000/03/28 20:39:05 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:
! 645: if (c->efd != -1) {
! 646: if (c->extended_usage == CHAN_EXTENDED_WRITE &&
! 647: FD_ISSET(c->efd, writeset) &&
! 648: buffer_len(&c->extended) > 0) {
! 649: len = write(c->efd, buffer_ptr(&c->extended),
! 650: buffer_len(&c->extended));
! 651: debug("channel %d: written %d to efd %d",
! 652: c->self, len, c->efd);
! 653: if (len > 0) {
! 654: buffer_consume(&c->extended, len);
! 655: c->local_consumed += len;
! 656: }
! 657: } else if (c->extended_usage == CHAN_EXTENDED_READ &&
! 658: FD_ISSET(c->efd, readset)) {
! 659: len = read(c->efd, buf, sizeof(buf));
! 660: debug("channel %d: read %d from efd %d",
! 661: c->self, len, c->efd);
! 662: if (len > 0)
! 663: buffer_append(&c->extended, buf, len);
! 664: }
! 665: }
! 666: return 1;
! 667: }
! 668: int
! 669: channel_check_window(Channel *c, fd_set * readset, fd_set * writeset)
! 670: {
! 671: if (!(c->flags & CHAN_CLOSE_SENT) &&
! 672: c->local_window < c->local_window_max/2 &&
! 673: c->local_consumed > 0) {
! 674: packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
! 675: packet_put_int(c->remote_id);
! 676: packet_put_int(c->local_consumed);
! 677: packet_send();
! 678: debug("channel %d: window %d sent adjust %d",
! 679: c->self, c->local_window,
! 680: c->local_consumed);
! 681: c->local_window += c->local_consumed;
! 682: c->local_consumed = 0;
1.1 deraadt 683: }
1.41 markus 684: return 1;
1.1 deraadt 685: }
686:
1.41 markus 687: void
688: channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
689: {
690: channel_handle_rfd(c, readset, writeset);
691: channel_handle_wfd(c, readset, writeset);
692: }
1.1 deraadt 693:
1.41 markus 694: void
1.44 ! markus 695: channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
! 696: {
! 697: channel_handle_rfd(c, readset, writeset);
! 698: channel_handle_wfd(c, readset, writeset);
! 699: channel_handle_efd(c, readset, writeset);
! 700: channel_check_window(c, readset, writeset);
! 701: }
! 702:
! 703: void
1.41 markus 704: channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1.1 deraadt 705: {
1.41 markus 706: int len;
707: /* Send buffered output data to the socket. */
708: if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
709: len = write(c->sock, buffer_ptr(&c->output),
710: buffer_len(&c->output));
711: if (len <= 0)
712: buffer_consume(&c->output, buffer_len(&c->output));
713: else
714: buffer_consume(&c->output, len);
715: }
716: }
1.25 markus 717:
1.41 markus 718: void
1.44 ! markus 719: channel_handler_init_20(void)
! 720: {
! 721: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
! 722: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
! 723:
! 724: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
! 725: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
! 726: }
! 727:
! 728: void
1.41 markus 729: channel_handler_init_13(void)
730: {
731: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
732: channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
733: channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
734: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
735: channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
736: channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
737: channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1.25 markus 738:
1.41 markus 739: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
740: channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
741: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
742: channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
743: channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
744: }
1.25 markus 745:
1.41 markus 746: void
747: channel_handler_init_15(void)
748: {
749: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
750: channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_15;
751: channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
752: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
753: channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1.25 markus 754:
1.41 markus 755: channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
756: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
757: channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
758: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
759: }
1.27 markus 760:
1.41 markus 761: void
762: channel_handler_init(void)
763: {
764: int i;
765: for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
766: channel_pre[i] = NULL;
767: channel_post[i] = NULL;
768: }
1.44 ! markus 769: if (compat20)
! 770: channel_handler_init_20();
! 771: else if (compat13)
1.41 markus 772: channel_handler_init_13();
773: else
774: channel_handler_init_15();
775: }
1.25 markus 776:
1.41 markus 777: void
778: channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
779: {
780: static int did_init = 0;
781: int i;
782: Channel *c;
1.25 markus 783:
1.41 markus 784: if (!did_init) {
785: channel_handler_init();
786: did_init = 1;
787: }
788: for (i = 0; i < channels_alloc; i++) {
789: c = &channels[i];
790: if (c->type == SSH_CHANNEL_FREE)
791: continue;
792: if (ftab[c->type] == NULL)
1.25 markus 793: continue;
1.41 markus 794: (*ftab[c->type])(c, readset, writeset);
1.44 ! markus 795: chan_delete_if_full_closed(c);
1.1 deraadt 796: }
797: }
798:
1.41 markus 799: void
800: channel_prepare_select(fd_set * readset, fd_set * writeset)
801: {
802: channel_handler(channel_pre, readset, writeset);
803: }
804:
805: void
806: channel_after_select(fd_set * readset, fd_set * writeset)
807: {
808: channel_handler(channel_post, readset, writeset);
809: }
810:
1.1 deraadt 811: /* If there is data to send to the connection, send some of it now. */
812:
1.25 markus 813: void
814: channel_output_poll()
1.1 deraadt 815: {
1.25 markus 816: int len, i;
1.41 markus 817: Channel *c;
1.1 deraadt 818:
1.25 markus 819: for (i = 0; i < channels_alloc; i++) {
1.41 markus 820: c = &channels[i];
1.37 markus 821:
1.27 markus 822: /* We are only interested in channels that can have buffered incoming data. */
1.37 markus 823: if (compat13) {
1.41 markus 824: if (c->type != SSH_CHANNEL_OPEN &&
825: c->type != SSH_CHANNEL_INPUT_DRAINING)
1.37 markus 826: continue;
827: } else {
1.41 markus 828: if (c->type != SSH_CHANNEL_OPEN)
1.37 markus 829: continue;
1.41 markus 830: if (c->istate != CHAN_INPUT_OPEN &&
831: c->istate != CHAN_INPUT_WAIT_DRAIN)
1.37 markus 832: continue;
833: }
1.44 ! markus 834: if (compat20 && (c->flags & CHAN_CLOSE_SENT)) {
! 835: debug("channel: %d: no data after CLOSE", c->self);
! 836: continue;
! 837: }
1.25 markus 838:
839: /* Get the amount of buffered data for this channel. */
1.41 markus 840: len = buffer_len(&c->input);
1.25 markus 841: if (len > 0) {
1.27 markus 842: /* Send some data for the other side over the secure connection. */
1.44 ! markus 843: if (compat20) {
! 844: if (len > c->remote_window)
! 845: len = c->remote_window;
! 846: if (len > c->remote_maxpacket)
! 847: len = c->remote_maxpacket;
1.25 markus 848: } else {
1.44 ! markus 849: if (packet_is_interactive()) {
! 850: if (len > 1024)
! 851: len = 512;
! 852: } else {
! 853: /* Keep the packets at reasonable size. */
! 854: if (len > packet_get_maxsize()/2)
! 855: len = packet_get_maxsize()/2;
! 856: }
1.25 markus 857: }
1.41 markus 858: if (len > 0) {
1.44 ! markus 859: packet_start(compat20 ?
! 860: SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1.41 markus 861: packet_put_int(c->remote_id);
862: packet_put_string(buffer_ptr(&c->input), len);
863: packet_send();
864: buffer_consume(&c->input, len);
865: c->remote_window -= len;
1.44 ! markus 866: debug("channel %d: send data len %d", c->self, len);
1.41 markus 867: }
868: } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1.25 markus 869: if (compat13)
870: fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1.27 markus 871: /*
872: * input-buffer is empty and read-socket shutdown:
873: * tell peer, that we will not send more data: send IEOF
874: */
1.41 markus 875: chan_ibuf_empty(c);
1.25 markus 876: }
1.44 ! markus 877: /* Send extended data, i.e. stderr */
! 878: if (compat20 &&
! 879: c->remote_window > 0 &&
! 880: (len = buffer_len(&c->extended)) > 0 &&
! 881: c->extended_usage == CHAN_EXTENDED_READ) {
! 882: if (len > c->remote_window)
! 883: len = c->remote_window;
! 884: if (len > c->remote_maxpacket)
! 885: len = c->remote_maxpacket;
! 886: packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
! 887: packet_put_int(c->remote_id);
! 888: packet_put_int(SSH2_EXTENDED_DATA_STDERR);
! 889: packet_put_string(buffer_ptr(&c->extended), len);
! 890: packet_send();
! 891: buffer_consume(&c->extended, len);
! 892: c->remote_window -= len;
! 893: }
1.25 markus 894: }
1.1 deraadt 895: }
896:
1.27 markus 897: /*
898: * This is called when a packet of type CHANNEL_DATA has just been received.
899: * The message type has already been consumed, but channel number and data is
900: * still there.
901: */
1.1 deraadt 902:
1.25 markus 903: void
1.41 markus 904: channel_input_data(int type, int plen)
1.1 deraadt 905: {
1.37 markus 906: int id;
1.25 markus 907: char *data;
908: unsigned int data_len;
1.41 markus 909: Channel *c;
1.25 markus 910:
911: /* Get the channel number and verify it. */
1.37 markus 912: id = packet_get_int();
1.41 markus 913: c = channel_lookup(id);
914: if (c == NULL)
1.37 markus 915: packet_disconnect("Received data for nonexistent channel %d.", id);
1.25 markus 916:
917: /* Ignore any data for non-open channels (might happen on close) */
1.41 markus 918: if (c->type != SSH_CHANNEL_OPEN &&
919: c->type != SSH_CHANNEL_X11_OPEN)
1.37 markus 920: return;
921:
922: /* same for protocol 1.5 if output end is no longer open */
1.41 markus 923: if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1.25 markus 924: return;
925:
926: /* Get the data. */
927: data = packet_get_string(&data_len);
1.41 markus 928:
1.44 ! markus 929: if (compat20){
! 930: if (data_len > c->local_maxpacket) {
! 931: log("channel %d: rcvd big packet %d, maxpack %d",
! 932: c->self, data_len, c->local_maxpacket);
! 933: }
! 934: if (data_len > c->local_window) {
! 935: log("channel %d: rcvd too much data %d, win %d",
! 936: c->self, data_len, c->local_window);
! 937: xfree(data);
! 938: return;
! 939: }
! 940: c->local_window -= data_len;
! 941: }else{
! 942: packet_integrity_check(plen, 4 + 4 + data_len, type);
! 943: }
1.41 markus 944: buffer_append(&c->output, data, data_len);
1.25 markus 945: xfree(data);
1.1 deraadt 946: }
1.44 ! markus 947: void
! 948: channel_input_extended_data(int type, int plen)
! 949: {
! 950: int id;
! 951: int tcode;
! 952: char *data;
! 953: unsigned int data_len;
! 954: Channel *c;
! 955:
! 956: /* Get the channel number and verify it. */
! 957: id = packet_get_int();
! 958: c = channel_lookup(id);
! 959:
! 960: if (c == NULL)
! 961: packet_disconnect("Received extended_data for bad channel %d.", id);
! 962: if (c->type != SSH_CHANNEL_OPEN) {
! 963: log("channel %d: ext data for non open", id);
! 964: return;
! 965: }
! 966: tcode = packet_get_int();
! 967: if (c->efd == -1 ||
! 968: c->extended_usage != CHAN_EXTENDED_WRITE ||
! 969: tcode != SSH2_EXTENDED_DATA_STDERR) {
! 970: log("channel %d: bad ext data", c->self);
! 971: return;
! 972: }
! 973: data = packet_get_string(&data_len);
! 974: if (data_len > c->local_window) {
! 975: log("channel %d: rcvd too much extended_data %d, win %d",
! 976: c->self, data_len, c->local_window);
! 977: xfree(data);
! 978: return;
! 979: }
! 980: debug("channel %d: rcvd ext data %d", c->self, data_len);
! 981: c->local_window -= data_len;
! 982: buffer_append(&c->extended, data, data_len);
! 983: xfree(data);
! 984: }
! 985:
1.1 deraadt 986:
1.27 markus 987: /*
988: * Returns true if no channel has too much buffered data, and false if one or
989: * more channel is overfull.
990: */
1.1 deraadt 991:
1.25 markus 992: int
993: channel_not_very_much_buffered_data()
1.1 deraadt 994: {
1.25 markus 995: unsigned int i;
1.41 markus 996: Channel *c;
1.25 markus 997:
998: for (i = 0; i < channels_alloc; i++) {
1.41 markus 999: c = &channels[i];
1000: if (c->type == SSH_CHANNEL_OPEN) {
1.44 ! markus 1001: if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
1.41 markus 1002: debug("channel %d: big input buffer %d",
1003: c->self, buffer_len(&c->input));
1.25 markus 1004: return 0;
1.41 markus 1005: }
1006: if (buffer_len(&c->output) > packet_get_maxsize()) {
1007: debug("channel %d: big output buffer %d",
1008: c->self, buffer_len(&c->output));
1.25 markus 1009: return 0;
1.41 markus 1010: }
1.25 markus 1011: }
1.1 deraadt 1012: }
1.25 markus 1013: return 1;
1.1 deraadt 1014: }
1015:
1.41 markus 1016: void
1017: channel_input_ieof(int type, int plen)
1018: {
1019: int id;
1020: Channel *c;
1021:
1022: packet_integrity_check(plen, 4, type);
1023:
1024: id = packet_get_int();
1025: c = channel_lookup(id);
1026: if (c == NULL)
1027: packet_disconnect("Received ieof for nonexistent channel %d.", id);
1028: chan_rcvd_ieof(c);
1029: }
1.1 deraadt 1030:
1.25 markus 1031: void
1.41 markus 1032: channel_input_close(int type, int plen)
1.1 deraadt 1033: {
1.41 markus 1034: int id;
1035: Channel *c;
1.1 deraadt 1036:
1.41 markus 1037: packet_integrity_check(plen, 4, type);
1038:
1039: id = packet_get_int();
1040: c = channel_lookup(id);
1041: if (c == NULL)
1042: packet_disconnect("Received close for nonexistent channel %d.", id);
1.27 markus 1043:
1044: /*
1045: * Send a confirmation that we have closed the channel and no more
1046: * data is coming for it.
1047: */
1.25 markus 1048: packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1.41 markus 1049: packet_put_int(c->remote_id);
1.25 markus 1050: packet_send();
1051:
1.27 markus 1052: /*
1053: * If the channel is in closed state, we have sent a close request,
1054: * and the other side will eventually respond with a confirmation.
1055: * Thus, we cannot free the channel here, because then there would be
1056: * no-one to receive the confirmation. The channel gets freed when
1057: * the confirmation arrives.
1058: */
1.41 markus 1059: if (c->type != SSH_CHANNEL_CLOSED) {
1.27 markus 1060: /*
1061: * Not a closed channel - mark it as draining, which will
1062: * cause it to be freed later.
1063: */
1.41 markus 1064: buffer_consume(&c->input, buffer_len(&c->input));
1065: c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1.25 markus 1066: }
1.1 deraadt 1067: }
1068:
1.41 markus 1069: /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1070: void
1071: channel_input_oclose(int type, int plen)
1072: {
1073: int id = packet_get_int();
1074: Channel *c = channel_lookup(id);
1075: packet_integrity_check(plen, 4, type);
1076: if (c == NULL)
1077: packet_disconnect("Received oclose for nonexistent channel %d.", id);
1078: chan_rcvd_oclose(c);
1079: }
1.1 deraadt 1080:
1.25 markus 1081: void
1.41 markus 1082: channel_input_close_confirmation(int type, int plen)
1.1 deraadt 1083: {
1.41 markus 1084: int id = packet_get_int();
1085: Channel *c = channel_lookup(id);
1.1 deraadt 1086:
1.41 markus 1087: if (c == NULL)
1088: packet_disconnect("Received close confirmation for "
1089: "out-of-range channel %d.", id);
1090: if (c->type != SSH_CHANNEL_CLOSED)
1091: packet_disconnect("Received close confirmation for "
1092: "non-closed channel %d (type %d).", id, c->type);
1093: channel_free(c->self);
1.1 deraadt 1094: }
1095:
1.25 markus 1096: void
1.41 markus 1097: channel_input_open_confirmation(int type, int plen)
1.1 deraadt 1098: {
1.41 markus 1099: int id, remote_id;
1100: Channel *c;
1.1 deraadt 1101:
1.44 ! markus 1102: if (!compat20)
! 1103: packet_integrity_check(plen, 4 + 4, type);
1.25 markus 1104:
1.41 markus 1105: id = packet_get_int();
1106: c = channel_lookup(id);
1.25 markus 1107:
1.41 markus 1108: if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1109: packet_disconnect("Received open confirmation for "
1110: "non-opening channel %d.", id);
1111: remote_id = packet_get_int();
1.27 markus 1112: /* Record the remote channel number and mark that the channel is now open. */
1.41 markus 1113: c->remote_id = remote_id;
1114: c->type = SSH_CHANNEL_OPEN;
1.44 ! markus 1115:
! 1116: if (compat20) {
! 1117: c->remote_window = packet_get_int();
! 1118: c->remote_maxpacket = packet_get_int();
! 1119: if (c->cb_fn != NULL && c->cb_event == type) {
! 1120: debug("callback start");
! 1121: c->cb_fn(c->self, c->cb_arg);
! 1122: debug("callback done");
! 1123: }
! 1124: debug("channel %d: open confirm rwindow %d rmax %d", c->self,
! 1125: c->remote_window, c->remote_maxpacket);
! 1126: }
1.1 deraadt 1127: }
1128:
1.25 markus 1129: void
1.41 markus 1130: channel_input_open_failure(int type, int plen)
1.1 deraadt 1131: {
1.41 markus 1132: int id;
1133: Channel *c;
1134:
1.44 ! markus 1135: if (!compat20)
! 1136: packet_integrity_check(plen, 4, type);
1.41 markus 1137:
1138: id = packet_get_int();
1139: c = channel_lookup(id);
1.25 markus 1140:
1.41 markus 1141: if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1142: packet_disconnect("Received open failure for "
1143: "non-opening channel %d.", id);
1.44 ! markus 1144: if (compat20) {
! 1145: int reason = packet_get_int();
! 1146: char *msg = packet_get_string(NULL);
! 1147: log("channel_open_failure: %d: reason %d: %s", id, reason, msg);
! 1148: xfree(msg);
! 1149: }
1.25 markus 1150: /* Free the channel. This will also close the socket. */
1.41 markus 1151: channel_free(id);
1.1 deraadt 1152: }
1153:
1.44 ! markus 1154: void
! 1155: channel_input_channel_request(int type, int plen)
! 1156: {
! 1157: int id;
! 1158: Channel *c;
! 1159:
! 1160: id = packet_get_int();
! 1161: c = channel_lookup(id);
! 1162:
! 1163: if (c == NULL ||
! 1164: (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
! 1165: packet_disconnect("Received request for "
! 1166: "non-open channel %d.", id);
! 1167: if (c->cb_fn != NULL && c->cb_event == type) {
! 1168: debug("callback start");
! 1169: c->cb_fn(c->self, c->cb_arg);
! 1170: debug("callback done");
! 1171: } else {
! 1172: char *service = packet_get_string(NULL);
! 1173: debug("channel: %d rcvd request for %s", c->self, service);
! 1174: debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
! 1175: xfree(service);
! 1176: }
! 1177: }
! 1178:
! 1179: void
! 1180: channel_input_window_adjust(int type, int plen)
! 1181: {
! 1182: Channel *c;
! 1183: int id, adjust;
! 1184:
! 1185: if (!compat20)
! 1186: return;
! 1187:
! 1188: /* Get the channel number and verify it. */
! 1189: id = packet_get_int();
! 1190: c = channel_lookup(id);
! 1191:
! 1192: if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
! 1193: log("Received window adjust for "
! 1194: "non-open channel %d.", id);
! 1195: return;
! 1196: }
! 1197: adjust = packet_get_int();
! 1198: debug("channel %d: rcvd adjust %d", id, adjust);
! 1199: c->remote_window += adjust;
! 1200: }
! 1201:
1.27 markus 1202: /*
1203: * Stops listening for channels, and removes any unix domain sockets that we
1204: * might have.
1205: */
1.1 deraadt 1206:
1.25 markus 1207: void
1208: channel_stop_listening()
1.1 deraadt 1209: {
1.25 markus 1210: int i;
1211: for (i = 0; i < channels_alloc; i++) {
1212: switch (channels[i].type) {
1213: case SSH_CHANNEL_AUTH_SOCKET:
1214: close(channels[i].sock);
1215: remove(channels[i].path);
1216: channel_free(i);
1217: break;
1218: case SSH_CHANNEL_PORT_LISTENER:
1219: case SSH_CHANNEL_X11_LISTENER:
1220: close(channels[i].sock);
1221: channel_free(i);
1222: break;
1223: default:
1224: break;
1225: }
1.1 deraadt 1226: }
1227: }
1228:
1.27 markus 1229: /*
1230: * Closes the sockets of all channels. This is used to close extra file
1231: * descriptors after a fork.
1232: */
1.1 deraadt 1233:
1.25 markus 1234: void
1235: channel_close_all()
1.1 deraadt 1236: {
1.25 markus 1237: int i;
1238: for (i = 0; i < channels_alloc; i++) {
1239: if (channels[i].type != SSH_CHANNEL_FREE)
1240: close(channels[i].sock);
1241: }
1.1 deraadt 1242: }
1243:
1244: /* Returns the maximum file descriptor number used by the channels. */
1245:
1.25 markus 1246: int
1247: channel_max_fd()
1.1 deraadt 1248: {
1.25 markus 1249: return channel_max_fd_value;
1.1 deraadt 1250: }
1251:
1252: /* Returns true if any channel is still open. */
1253:
1.25 markus 1254: int
1255: channel_still_open()
1.1 deraadt 1256: {
1.25 markus 1257: unsigned int i;
1258: for (i = 0; i < channels_alloc; i++)
1259: switch (channels[i].type) {
1260: case SSH_CHANNEL_FREE:
1261: case SSH_CHANNEL_X11_LISTENER:
1262: case SSH_CHANNEL_PORT_LISTENER:
1263: case SSH_CHANNEL_CLOSED:
1264: case SSH_CHANNEL_AUTH_SOCKET:
1265: continue;
1.44 ! markus 1266: case SSH_CHANNEL_LARVAL:
! 1267: if (!compat20)
! 1268: fatal("cannot happen: SSH_CHANNEL_LARVAL");
! 1269: continue;
1.25 markus 1270: case SSH_CHANNEL_OPENING:
1271: case SSH_CHANNEL_OPEN:
1272: case SSH_CHANNEL_X11_OPEN:
1273: return 1;
1274: case SSH_CHANNEL_INPUT_DRAINING:
1275: case SSH_CHANNEL_OUTPUT_DRAINING:
1276: if (!compat13)
1277: fatal("cannot happen: OUT_DRAIN");
1278: return 1;
1279: default:
1280: fatal("channel_still_open: bad channel type %d", channels[i].type);
1281: /* NOTREACHED */
1282: }
1283: return 0;
1.1 deraadt 1284: }
1285:
1.27 markus 1286: /*
1287: * Returns a message describing the currently open forwarded connections,
1288: * suitable for sending to the client. The message contains crlf pairs for
1289: * newlines.
1290: */
1.1 deraadt 1291:
1.25 markus 1292: char *
1293: channel_open_message()
1.1 deraadt 1294: {
1.25 markus 1295: Buffer buffer;
1296: int i;
1297: char buf[512], *cp;
1298:
1299: buffer_init(&buffer);
1300: snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1.1 deraadt 1301: buffer_append(&buffer, buf, strlen(buf));
1.25 markus 1302: for (i = 0; i < channels_alloc; i++) {
1303: Channel *c = &channels[i];
1304: switch (c->type) {
1305: case SSH_CHANNEL_FREE:
1306: case SSH_CHANNEL_X11_LISTENER:
1307: case SSH_CHANNEL_PORT_LISTENER:
1308: case SSH_CHANNEL_CLOSED:
1309: case SSH_CHANNEL_AUTH_SOCKET:
1310: continue;
1.44 ! markus 1311: case SSH_CHANNEL_LARVAL:
1.25 markus 1312: case SSH_CHANNEL_OPENING:
1313: case SSH_CHANNEL_OPEN:
1314: case SSH_CHANNEL_X11_OPEN:
1315: case SSH_CHANNEL_INPUT_DRAINING:
1316: case SSH_CHANNEL_OUTPUT_DRAINING:
1.41 markus 1317: snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1.37 markus 1318: c->self, c->remote_name,
1319: c->type, c->remote_id,
1320: c->istate, buffer_len(&c->input),
1.41 markus 1321: c->ostate, buffer_len(&c->output),
1322: c->rfd, c->wfd);
1.25 markus 1323: buffer_append(&buffer, buf, strlen(buf));
1324: continue;
1325: default:
1.41 markus 1326: fatal("channel_open_message: bad channel type %d", c->type);
1.25 markus 1327: /* NOTREACHED */
1328: }
1329: }
1330: buffer_append(&buffer, "\0", 1);
1331: cp = xstrdup(buffer_ptr(&buffer));
1332: buffer_free(&buffer);
1333: return cp;
1.1 deraadt 1334: }
1335:
1.27 markus 1336: /*
1337: * Initiate forwarding of connections to local port "port" through the secure
1338: * channel to host:port from remote side.
1339: */
1.1 deraadt 1340:
1.25 markus 1341: void
1.31 markus 1342: channel_request_local_forwarding(u_short port, const char *host,
1.33 markus 1343: u_short host_port, int gateway_ports)
1.25 markus 1344: {
1.35 markus 1345: int success, ch, sock, on = 1;
1346: struct addrinfo hints, *ai, *aitop;
1347: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.28 markus 1348: struct linger linger;
1.25 markus 1349:
1350: if (strlen(host) > sizeof(channels[0].path) - 1)
1351: packet_disconnect("Forward host name too long.");
1352:
1.28 markus 1353: /*
1.35 markus 1354: * getaddrinfo returns a loopback address if the hostname is
1355: * set to NULL and hints.ai_flags is not AI_PASSIVE
1.28 markus 1356: */
1.35 markus 1357: memset(&hints, 0, sizeof(hints));
1358: hints.ai_family = IPv4or6;
1359: hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1360: hints.ai_socktype = SOCK_STREAM;
1361: snprintf(strport, sizeof strport, "%d", port);
1362: if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1363: packet_disconnect("getaddrinfo: fatal error");
1364:
1365: success = 0;
1366: for (ai = aitop; ai; ai = ai->ai_next) {
1367: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1368: continue;
1369: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1370: strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1371: error("channel_request_local_forwarding: getnameinfo failed");
1372: continue;
1373: }
1374: /* Create a port to listen for the host. */
1375: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1376: if (sock < 0) {
1377: /* this is no error since kernel may not support ipv6 */
1378: verbose("socket: %.100s", strerror(errno));
1379: continue;
1380: }
1381: /*
1382: * Set socket options. We would like the socket to disappear
1383: * as soon as it has been closed for whatever reason.
1384: */
1385: setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1386: linger.l_onoff = 1;
1387: linger.l_linger = 5;
1388: setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1389: debug("Local forwarding listening on %s port %s.", ntop, strport);
1390:
1391: /* Bind the socket to the address. */
1392: if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1393: /* address can be in use ipv6 address is already bound */
1394: verbose("bind: %.100s", strerror(errno));
1395: close(sock);
1396: continue;
1397: }
1398: /* Start listening for connections on the socket. */
1399: if (listen(sock, 5) < 0) {
1400: error("listen: %.100s", strerror(errno));
1401: close(sock);
1402: continue;
1403: }
1404: /* Allocate a channel number for the socket. */
1.41 markus 1405: ch = channel_new(
1406: "port listener", SSH_CHANNEL_PORT_LISTENER,
1407: sock, sock, -1,
1408: CHAN_WINDOW_DEFAULT, CHAN_PACKET_DEFAULT,
1409: 0, xstrdup("port listener"));
1.35 markus 1410: strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
1411: channels[ch].host_port = host_port;
1412: channels[ch].listening_port = port;
1413: success = 1;
1414: }
1415: if (success == 0)
1416: packet_disconnect("cannot listen port: %d", port);
1417: freeaddrinfo(aitop);
1.25 markus 1418: }
1.1 deraadt 1419:
1.27 markus 1420: /*
1421: * Initiate forwarding of connections to port "port" on remote host through
1422: * the secure channel to host:port from local side.
1423: */
1.1 deraadt 1424:
1.25 markus 1425: void
1.41 markus 1426: channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect,
1427: u_short port_to_connect)
1.25 markus 1428: {
1429: int payload_len;
1430: /* Record locally that connection to this host/port is permitted. */
1431: if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1432: fatal("channel_request_remote_forwarding: too many forwards");
1433:
1.41 markus 1434: permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
1435: permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
1436: permitted_opens[num_permitted_opens].listen_port = listen_port;
1.25 markus 1437: num_permitted_opens++;
1438:
1439: /* Send the forward request to the remote side. */
1.44 ! markus 1440: if (compat20) {
! 1441: const char *address_to_bind = "0.0.0.0";
! 1442: packet_start(SSH2_MSG_GLOBAL_REQUEST);
! 1443: packet_put_cstring("tcpip-forward");
! 1444: packet_put_char(0); /* boolean: want reply */
! 1445: packet_put_cstring(address_to_bind);
! 1446: packet_put_int(listen_port);
! 1447: } else {
! 1448: packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
! 1449: packet_put_int(port_to_connect);
! 1450: packet_put_cstring(host_to_connect);
! 1451: packet_put_int(listen_port);
! 1452: packet_send();
! 1453: packet_write_wait();
! 1454: /*
! 1455: * Wait for response from the remote side. It will send a disconnect
! 1456: * message on failure, and we will never see it here.
! 1457: */
! 1458: packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
! 1459: }
1.1 deraadt 1460: }
1461:
1.27 markus 1462: /*
1463: * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1464: * listening for the port, and sends back a success reply (or disconnect
1465: * message if there was an error). This never returns if there was an error.
1466: */
1.1 deraadt 1467:
1.25 markus 1468: void
1469: channel_input_port_forward_request(int is_root)
1.1 deraadt 1470: {
1.31 markus 1471: u_short port, host_port;
1.25 markus 1472: char *hostname;
1.1 deraadt 1473:
1.25 markus 1474: /* Get arguments from the packet. */
1475: port = packet_get_int();
1476: hostname = packet_get_string(NULL);
1477: host_port = packet_get_int();
1478:
1.27 markus 1479: /*
1480: * Check that an unprivileged user is not trying to forward a
1481: * privileged port.
1482: */
1.25 markus 1483: if (port < IPPORT_RESERVED && !is_root)
1484: packet_disconnect("Requested forwarding of port %d but user is not root.",
1485: port);
1.33 markus 1486: /*
1487: * Initiate forwarding,
1488: * bind port to localhost only (gateway ports == 0).
1489: */
1490: channel_request_local_forwarding(port, hostname, host_port, 0);
1.25 markus 1491:
1492: /* Free the argument string. */
1493: xfree(hostname);
1.1 deraadt 1494: }
1495:
1.41 markus 1496: /* XXX move to aux.c */
1497: int
1498: channel_connect_to(const char *host, u_short host_port)
1499: {
1500: struct addrinfo hints, *ai, *aitop;
1501: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1502: int gaierr;
1503: int sock = -1;
1504:
1505: memset(&hints, 0, sizeof(hints));
1506: hints.ai_family = IPv4or6;
1507: hints.ai_socktype = SOCK_STREAM;
1508: snprintf(strport, sizeof strport, "%d", host_port);
1509: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
1510: error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
1511: return -1;
1512: }
1513: for (ai = aitop; ai; ai = ai->ai_next) {
1514: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1515: continue;
1516: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1517: strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1518: error("channel_connect_to: getnameinfo failed");
1519: continue;
1520: }
1521: /* Create the socket. */
1522: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1523: if (sock < 0) {
1524: error("socket: %.100s", strerror(errno));
1525: continue;
1526: }
1527: /* Connect to the host/port. */
1528: if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1529: error("connect %.100s port %s: %.100s", ntop, strport,
1530: strerror(errno));
1531: close(sock);
1532: continue; /* fail -- try next */
1533: }
1534: break; /* success */
1535:
1536: }
1537: freeaddrinfo(aitop);
1538: if (!ai) {
1539: error("connect %.100s port %d: failed.", host, host_port);
1540: return -1;
1541: }
1542: /* success */
1543: return sock;
1544: }
1.27 markus 1545: /*
1546: * This is called after receiving PORT_OPEN message. This attempts to
1547: * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
1548: * or CHANNEL_OPEN_FAILURE.
1549: */
1.1 deraadt 1550:
1.25 markus 1551: void
1.41 markus 1552: channel_input_port_open(int type, int plen)
1.1 deraadt 1553: {
1.31 markus 1554: u_short host_port;
1.25 markus 1555: char *host, *originator_string;
1.41 markus 1556: int remote_channel, sock = -1, newch, i, denied;
1.39 markus 1557: unsigned int host_len, originator_len;
1.25 markus 1558:
1559: /* Get remote channel number. */
1560: remote_channel = packet_get_int();
1561:
1562: /* Get host name to connect to. */
1563: host = packet_get_string(&host_len);
1564:
1565: /* Get port to connect to. */
1566: host_port = packet_get_int();
1567:
1568: /* Get remote originator name. */
1.29 markus 1569: if (have_hostname_in_open) {
1.25 markus 1570: originator_string = packet_get_string(&originator_len);
1.29 markus 1571: originator_len += 4; /* size of packet_int */
1572: } else {
1.25 markus 1573: originator_string = xstrdup("unknown (remote did not supply name)");
1.29 markus 1574: originator_len = 0; /* no originator supplied */
1575: }
1.25 markus 1576:
1.41 markus 1577: packet_integrity_check(plen,
1578: 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
1.25 markus 1579:
1580: /* Check if opening that port is permitted. */
1.41 markus 1581: denied = 0;
1.25 markus 1582: if (!all_opens_permitted) {
1583: /* Go trough all permitted ports. */
1584: for (i = 0; i < num_permitted_opens; i++)
1.41 markus 1585: if (permitted_opens[i].port_to_connect == host_port &&
1586: strcmp(permitted_opens[i].host_to_connect, host) == 0)
1.25 markus 1587: break;
1588:
1589: /* Check if we found the requested port among those permitted. */
1590: if (i >= num_permitted_opens) {
1591: /* The port is not permitted. */
1592: log("Received request to connect to %.100s:%d, but the request was denied.",
1593: host, host_port);
1.41 markus 1594: denied = 1;
1.25 markus 1595: }
1596: }
1.41 markus 1597: sock = denied ? -1 : channel_connect_to(host, host_port);
1598: if (sock > 0) {
1599: /* Allocate a channel for this connection. */
1600: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
1601: channels[newch].remote_id = remote_channel;
1602:
1603: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1604: packet_put_int(remote_channel);
1605: packet_put_int(newch);
1606: packet_send();
1607: } else {
1608: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1609: packet_put_int(remote_channel);
1610: packet_send();
1.25 markus 1611: }
1612: xfree(host);
1.1 deraadt 1613: }
1614:
1.27 markus 1615: /*
1616: * Creates an internet domain socket for listening for X11 connections.
1617: * Returns a suitable value for the DISPLAY variable, or NULL if an error
1618: * occurs.
1619: */
1.1 deraadt 1620:
1.35 markus 1621: #define NUM_SOCKS 10
1622:
1.25 markus 1623: char *
1.33 markus 1624: x11_create_display_inet(int screen_number, int x11_display_offset)
1.1 deraadt 1625: {
1.31 markus 1626: int display_number, sock;
1627: u_short port;
1.35 markus 1628: struct addrinfo hints, *ai, *aitop;
1629: char strport[NI_MAXSERV];
1630: int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
1631: char display[512];
1.25 markus 1632: char hostname[MAXHOSTNAMELEN];
1633:
1.33 markus 1634: for (display_number = x11_display_offset;
1.25 markus 1635: display_number < MAX_DISPLAYS;
1636: display_number++) {
1637: port = 6000 + display_number;
1.35 markus 1638: memset(&hints, 0, sizeof(hints));
1639: hints.ai_family = IPv4or6;
1.36 markus 1640: hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
1.35 markus 1641: hints.ai_socktype = SOCK_STREAM;
1642: snprintf(strport, sizeof strport, "%d", port);
1643: if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
1644: error("getaddrinfo: %.100s", gai_strerror(gaierr));
1.25 markus 1645: return NULL;
1646: }
1.35 markus 1647: for (ai = aitop; ai; ai = ai->ai_next) {
1648: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1649: continue;
1650: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1651: if (sock < 0) {
1652: error("socket: %.100s", strerror(errno));
1653: return NULL;
1654: }
1655: if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1656: debug("bind port %d: %.100s", port, strerror(errno));
1657: shutdown(sock, SHUT_RDWR);
1658: close(sock);
1659: for (n = 0; n < num_socks; n++) {
1660: shutdown(socks[n], SHUT_RDWR);
1661: close(socks[n]);
1662: }
1663: num_socks = 0;
1664: break;
1665: }
1666: socks[num_socks++] = sock;
1667: if (num_socks == NUM_SOCKS)
1668: break;
1.25 markus 1669: }
1.35 markus 1670: if (num_socks > 0)
1671: break;
1.25 markus 1672: }
1673: if (display_number >= MAX_DISPLAYS) {
1674: error("Failed to allocate internet-domain X11 display socket.");
1675: return NULL;
1676: }
1677: /* Start listening for connections on the socket. */
1.35 markus 1678: for (n = 0; n < num_socks; n++) {
1679: sock = socks[n];
1680: if (listen(sock, 5) < 0) {
1681: error("listen: %.100s", strerror(errno));
1682: shutdown(sock, SHUT_RDWR);
1683: close(sock);
1684: return NULL;
1685: }
1.25 markus 1686: }
1.35 markus 1687:
1.25 markus 1688: /* Set up a suitable value for the DISPLAY variable. */
1689: if (gethostname(hostname, sizeof(hostname)) < 0)
1690: fatal("gethostname: %.100s", strerror(errno));
1.35 markus 1691: snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1.25 markus 1692: display_number, screen_number);
1693:
1.35 markus 1694: /* Allocate a channel for each socket. */
1695: for (n = 0; n < num_socks; n++) {
1696: sock = socks[n];
1697: (void) channel_allocate(SSH_CHANNEL_X11_LISTENER, sock,
1698: xstrdup("X11 inet listener"));
1699: }
1.1 deraadt 1700:
1.25 markus 1701: /* Return a suitable value for the DISPLAY environment variable. */
1.35 markus 1702: return xstrdup(display);
1.1 deraadt 1703: }
1704:
1705: #ifndef X_UNIX_PATH
1706: #define X_UNIX_PATH "/tmp/.X11-unix/X"
1707: #endif
1708:
1709: static
1710: int
1.30 deraadt 1711: connect_local_xsocket(unsigned int dnr)
1.1 deraadt 1712: {
1.25 markus 1713: static const char *const x_sockets[] = {
1714: X_UNIX_PATH "%u",
1715: "/var/X/.X11-unix/X" "%u",
1716: "/usr/spool/sockets/X11/" "%u",
1717: NULL
1718: };
1719: int sock;
1720: struct sockaddr_un addr;
1721: const char *const * path;
1722:
1723: for (path = x_sockets; *path; ++path) {
1724: sock = socket(AF_UNIX, SOCK_STREAM, 0);
1725: if (sock < 0)
1726: error("socket: %.100s", strerror(errno));
1727: memset(&addr, 0, sizeof(addr));
1728: addr.sun_family = AF_UNIX;
1729: snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
1730: if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
1731: return sock;
1732: close(sock);
1733: }
1734: error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
1735: return -1;
1.1 deraadt 1736: }
1737:
1738:
1.27 markus 1739: /*
1740: * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
1741: * the remote channel number. We should do whatever we want, and respond
1742: * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
1743: */
1.1 deraadt 1744:
1.25 markus 1745: void
1.41 markus 1746: x11_input_open(int type, int plen)
1.1 deraadt 1747: {
1.35 markus 1748: int remote_channel, display_number, sock = 0, newch;
1.25 markus 1749: const char *display;
1750: char buf[1024], *cp, *remote_host;
1.39 markus 1751: unsigned int remote_len;
1.35 markus 1752: struct addrinfo hints, *ai, *aitop;
1753: char strport[NI_MAXSERV];
1754: int gaierr;
1.25 markus 1755:
1756: /* Get remote channel number. */
1757: remote_channel = packet_get_int();
1758:
1759: /* Get remote originator name. */
1.29 markus 1760: if (have_hostname_in_open) {
1.25 markus 1761: remote_host = packet_get_string(&remote_len);
1.29 markus 1762: remote_len += 4;
1763: } else {
1.25 markus 1764: remote_host = xstrdup("unknown (remote did not supply name)");
1.29 markus 1765: remote_len = 0;
1766: }
1.25 markus 1767:
1768: debug("Received X11 open request.");
1.41 markus 1769: packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
1.25 markus 1770:
1771: /* Try to open a socket for the local X server. */
1772: display = getenv("DISPLAY");
1773: if (!display) {
1774: error("DISPLAY not set.");
1775: goto fail;
1776: }
1.27 markus 1777: /*
1778: * Now we decode the value of the DISPLAY variable and make a
1779: * connection to the real X server.
1780: */
1781:
1782: /*
1783: * Check if it is a unix domain socket. Unix domain displays are in
1784: * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
1785: */
1.25 markus 1786: if (strncmp(display, "unix:", 5) == 0 ||
1787: display[0] == ':') {
1788: /* Connect to the unix domain socket. */
1789: if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
1790: error("Could not parse display number from DISPLAY: %.100s",
1791: display);
1792: goto fail;
1793: }
1794: /* Create a socket. */
1795: sock = connect_local_xsocket(display_number);
1796: if (sock < 0)
1797: goto fail;
1798:
1799: /* OK, we now have a connection to the display. */
1800: goto success;
1801: }
1.27 markus 1802: /*
1803: * Connect to an inet socket. The DISPLAY value is supposedly
1804: * hostname:d[.s], where hostname may also be numeric IP address.
1805: */
1.25 markus 1806: strncpy(buf, display, sizeof(buf));
1807: buf[sizeof(buf) - 1] = 0;
1808: cp = strchr(buf, ':');
1809: if (!cp) {
1810: error("Could not find ':' in DISPLAY: %.100s", display);
1811: goto fail;
1812: }
1813: *cp = 0;
1.27 markus 1814: /* buf now contains the host name. But first we parse the display number. */
1.25 markus 1815: if (sscanf(cp + 1, "%d", &display_number) != 1) {
1816: error("Could not parse display number from DISPLAY: %.100s",
1817: display);
1818: goto fail;
1819: }
1.35 markus 1820:
1821: /* Look up the host address */
1822: memset(&hints, 0, sizeof(hints));
1823: hints.ai_family = IPv4or6;
1824: hints.ai_socktype = SOCK_STREAM;
1825: snprintf(strport, sizeof strport, "%d", 6000 + display_number);
1826: if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
1827: error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
1.25 markus 1828: goto fail;
1829: }
1.35 markus 1830: for (ai = aitop; ai; ai = ai->ai_next) {
1831: /* Create a socket. */
1832: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1833: if (sock < 0) {
1834: debug("socket: %.100s", strerror(errno));
1.41 markus 1835: continue;
1836: }
1837: /* Connect it to the display. */
1838: if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1839: debug("connect %.100s port %d: %.100s", buf,
1840: 6000 + display_number, strerror(errno));
1841: close(sock);
1842: continue;
1843: }
1844: /* Success */
1845: break;
1.35 markus 1846: }
1847: freeaddrinfo(aitop);
1848: if (!ai) {
1849: error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
1850: strerror(errno));
1.25 markus 1851: goto fail;
1852: }
1853: success:
1854: /* We have successfully obtained a connection to the real X display. */
1855:
1856: /* Allocate a channel for this connection. */
1857: if (x11_saved_proto == NULL)
1858: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, remote_host);
1859: else
1860: newch = channel_allocate(SSH_CHANNEL_X11_OPEN, sock, remote_host);
1861: channels[newch].remote_id = remote_channel;
1862:
1863: /* Send a confirmation to the remote host. */
1864: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1865: packet_put_int(remote_channel);
1866: packet_put_int(newch);
1867: packet_send();
1868:
1869: return;
1870:
1871: fail:
1872: /* Send refusal to the remote host. */
1873: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1874: packet_put_int(remote_channel);
1875: packet_send();
1.1 deraadt 1876: }
1877:
1.27 markus 1878: /*
1879: * Requests forwarding of X11 connections, generates fake authentication
1880: * data, and enables authentication spoofing.
1881: */
1.1 deraadt 1882:
1.25 markus 1883: void
1884: x11_request_forwarding_with_spoofing(const char *proto, const char *data)
1.1 deraadt 1885: {
1.25 markus 1886: unsigned int data_len = (unsigned int) strlen(data) / 2;
1887: unsigned int i, value;
1888: char *new_data;
1889: int screen_number;
1890: const char *cp;
1891: u_int32_t rand = 0;
1892:
1893: cp = getenv("DISPLAY");
1894: if (cp)
1895: cp = strchr(cp, ':');
1896: if (cp)
1897: cp = strchr(cp, '.');
1898: if (cp)
1899: screen_number = atoi(cp + 1);
1900: else
1901: screen_number = 0;
1902:
1903: /* Save protocol name. */
1904: x11_saved_proto = xstrdup(proto);
1905:
1.27 markus 1906: /*
1907: * Extract real authentication data and generate fake data of the
1908: * same length.
1909: */
1.25 markus 1910: x11_saved_data = xmalloc(data_len);
1911: x11_fake_data = xmalloc(data_len);
1912: for (i = 0; i < data_len; i++) {
1913: if (sscanf(data + 2 * i, "%2x", &value) != 1)
1914: fatal("x11_request_forwarding: bad authentication data: %.100s", data);
1915: if (i % 4 == 0)
1916: rand = arc4random();
1917: x11_saved_data[i] = value;
1918: x11_fake_data[i] = rand & 0xff;
1919: rand >>= 8;
1920: }
1921: x11_saved_data_len = data_len;
1922: x11_fake_data_len = data_len;
1923:
1924: /* Convert the fake data into hex. */
1925: new_data = xmalloc(2 * data_len + 1);
1926: for (i = 0; i < data_len; i++)
1927: sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]);
1928:
1929: /* Send the request packet. */
1930: packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
1931: packet_put_string(proto, strlen(proto));
1932: packet_put_string(new_data, strlen(new_data));
1933: packet_put_int(screen_number);
1934: packet_send();
1935: packet_write_wait();
1936: xfree(new_data);
1.1 deraadt 1937: }
1938:
1939: /* Sends a message to the server to request authentication fd forwarding. */
1940:
1.25 markus 1941: void
1942: auth_request_forwarding()
1.1 deraadt 1943: {
1.25 markus 1944: packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
1945: packet_send();
1946: packet_write_wait();
1.1 deraadt 1947: }
1948:
1.27 markus 1949: /*
1950: * Returns the name of the forwarded authentication socket. Returns NULL if
1951: * there is no forwarded authentication socket. The returned value points to
1952: * a static buffer.
1953: */
1.1 deraadt 1954:
1.25 markus 1955: char *
1956: auth_get_socket_name()
1.1 deraadt 1957: {
1.25 markus 1958: return channel_forwarded_auth_socket_name;
1.1 deraadt 1959: }
1960:
1.12 markus 1961: /* removes the agent forwarding socket */
1962:
1.25 markus 1963: void
1964: cleanup_socket(void)
1965: {
1966: remove(channel_forwarded_auth_socket_name);
1967: rmdir(channel_forwarded_auth_socket_dir);
1.12 markus 1968: }
1969:
1.27 markus 1970: /*
1971: * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
1972: * This starts forwarding authentication requests.
1973: */
1.1 deraadt 1974:
1.25 markus 1975: void
1976: auth_input_request_forwarding(struct passwd * pw)
1.1 deraadt 1977: {
1.25 markus 1978: int sock, newch;
1979: struct sockaddr_un sunaddr;
1980:
1981: if (auth_get_socket_name() != NULL)
1982: fatal("Protocol error: authentication forwarding requested twice.");
1983:
1984: /* Temporarily drop privileged uid for mkdir/bind. */
1985: temporarily_use_uid(pw->pw_uid);
1986:
1987: /* Allocate a buffer for the socket name, and format the name. */
1988: channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
1989: channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
1990: strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
1991:
1992: /* Create private directory for socket */
1993: if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL)
1994: packet_disconnect("mkdtemp: %.100s", strerror(errno));
1995: snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
1996: channel_forwarded_auth_socket_dir, (int) getpid());
1997:
1998: if (atexit(cleanup_socket) < 0) {
1999: int saved = errno;
2000: cleanup_socket();
2001: packet_disconnect("socket: %.100s", strerror(saved));
2002: }
2003: /* Create the socket. */
2004: sock = socket(AF_UNIX, SOCK_STREAM, 0);
2005: if (sock < 0)
2006: packet_disconnect("socket: %.100s", strerror(errno));
2007:
2008: /* Bind it to the name. */
2009: memset(&sunaddr, 0, sizeof(sunaddr));
2010: sunaddr.sun_family = AF_UNIX;
2011: strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
2012: sizeof(sunaddr.sun_path));
2013:
2014: if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2015: packet_disconnect("bind: %.100s", strerror(errno));
2016:
2017: /* Restore the privileged uid. */
2018: restore_uid();
2019:
2020: /* Start listening on the socket. */
2021: if (listen(sock, 5) < 0)
2022: packet_disconnect("listen: %.100s", strerror(errno));
2023:
2024: /* Allocate a channel for the authentication agent socket. */
2025: newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock,
2026: xstrdup("auth socket"));
1.32 deraadt 2027: strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
2028: sizeof(channels[newch].path));
1.1 deraadt 2029: }
2030:
2031: /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2032:
1.25 markus 2033: void
1.41 markus 2034: auth_input_open_request(int type, int plen)
1.1 deraadt 2035: {
1.25 markus 2036: int remch, sock, newch;
2037: char *dummyname;
1.41 markus 2038:
2039: packet_integrity_check(plen, 4, type);
1.25 markus 2040:
2041: /* Read the remote channel number from the message. */
2042: remch = packet_get_int();
2043:
1.27 markus 2044: /*
2045: * Get a connection to the local authentication agent (this may again
2046: * get forwarded).
2047: */
1.25 markus 2048: sock = ssh_get_authentication_socket();
2049:
1.27 markus 2050: /*
2051: * If we could not connect the agent, send an error message back to
2052: * the server. This should never happen unless the agent dies,
2053: * because authentication forwarding is only enabled if we have an
2054: * agent.
2055: */
1.25 markus 2056: if (sock < 0) {
2057: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2058: packet_put_int(remch);
2059: packet_send();
2060: return;
2061: }
2062: debug("Forwarding authentication connection.");
1.1 deraadt 2063:
1.27 markus 2064: /*
2065: * Dummy host name. This will be freed when the channel is freed; it
2066: * will still be valid in the packet_put_string below since the
2067: * channel cannot yet be freed at that point.
2068: */
1.25 markus 2069: dummyname = xstrdup("authentication agent connection");
2070:
2071: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
2072: channels[newch].remote_id = remch;
2073:
2074: /* Send a confirmation to the remote host. */
2075: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2076: packet_put_int(remch);
2077: packet_put_int(newch);
1.44 ! markus 2078: packet_send();
! 2079: }
! 2080:
! 2081: void
! 2082: channel_open(int id)
! 2083: {
! 2084: Channel *c = channel_lookup(id);
! 2085: if (c == NULL) {
! 2086: log("channel_open: %d: bad id", id);
! 2087: return;
! 2088: }
! 2089: packet_start(SSH2_MSG_CHANNEL_OPEN);
! 2090: packet_put_cstring(c->ctype);
! 2091: packet_put_int(c->self);
! 2092: packet_put_int(c->local_window);
! 2093: packet_put_int(c->local_maxpacket);
! 2094: packet_send();
! 2095: debug("channel open %d", id);
! 2096: }
! 2097: void
! 2098: channel_request(int id, char *service, int wantconfirm)
! 2099: {
! 2100: channel_request_start(id, service, wantconfirm);
! 2101: packet_send();
! 2102: debug("channel request %d: %s", id, service) ;
! 2103: }
! 2104: void
! 2105: channel_request_start(int id, char *service, int wantconfirm)
! 2106: {
! 2107: Channel *c = channel_lookup(id);
! 2108: if (c == NULL) {
! 2109: log("channel_request: %d: bad id", id);
! 2110: return;
! 2111: }
! 2112: packet_start(SSH2_MSG_CHANNEL_REQUEST);
! 2113: packet_put_int(c->remote_id);
! 2114: packet_put_cstring(service);
! 2115: packet_put_char(wantconfirm);
! 2116: }
! 2117: void
! 2118: channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
! 2119: {
! 2120: Channel *c = channel_lookup(id);
! 2121: if (c == NULL) {
! 2122: log("channel_register_callback: %d: bad id", id);
! 2123: return;
! 2124: }
! 2125: c->cb_event = mtype;
! 2126: c->cb_fn = fn;
! 2127: c->cb_arg = arg;
! 2128: }
! 2129: void
! 2130: channel_register_cleanup(int id, channel_callback_fn *fn)
! 2131: {
! 2132: Channel *c = channel_lookup(id);
! 2133: if (c == NULL) {
! 2134: log("channel_register_cleanup: %d: bad id", id);
! 2135: return;
! 2136: }
! 2137: c->dettach_user = fn;
! 2138: }
! 2139: void
! 2140: channel_cancel_cleanup(int id)
! 2141: {
! 2142: Channel *c = channel_lookup(id);
! 2143: if (c == NULL) {
! 2144: log("channel_cancel_cleanup: %d: bad id", id);
! 2145: return;
! 2146: }
! 2147: c->dettach_user = NULL;
! 2148: }
! 2149:
! 2150: void
! 2151: channel_set_fds(int id, int rfd, int wfd, int efd, int extusage)
! 2152: {
! 2153: Channel *c = channel_lookup(id);
! 2154: if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
! 2155: fatal("channel_activate for non-larval channel %d.", id);
! 2156: if (rfd > channel_max_fd_value)
! 2157: channel_max_fd_value = rfd;
! 2158: if (wfd > channel_max_fd_value)
! 2159: channel_max_fd_value = wfd;
! 2160: if (efd > channel_max_fd_value)
! 2161: channel_max_fd_value = efd;
! 2162: c->type = SSH_CHANNEL_OPEN;
! 2163: c->rfd = rfd;
! 2164: c->wfd = wfd;
! 2165: c->efd = efd;
! 2166: c->extended_usage = extusage;
! 2167: /* XXX window size? */
! 2168: c->local_window = c->local_window_max = c->local_maxpacket/2;
! 2169: packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
! 2170: packet_put_int(c->remote_id);
! 2171: packet_put_int(c->local_window);
1.25 markus 2172: packet_send();
1.1 deraadt 2173: }
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