Annotation of src/usr.bin/ssh/channels.c, Revision 1.41
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: *
16: */
1.1 deraadt 17:
18: #include "includes.h"
1.41 ! markus 19: RCSID("$Id: channels.c,v 1.40 2000/03/27 17:41:50 markus Exp $");
1.1 deraadt 20:
21: #include "ssh.h"
22: #include "packet.h"
23: #include "xmalloc.h"
24: #include "buffer.h"
25: #include "authfd.h"
26: #include "uidswap.h"
1.20 markus 27: #include "readconf.h"
1.3 deraadt 28: #include "servconf.h"
1.1 deraadt 29:
1.14 markus 30: #include "channels.h"
31: #include "nchan.h"
32: #include "compat.h"
33:
1.1 deraadt 34: /* Maximum number of fake X11 displays to try. */
35: #define MAX_DISPLAYS 1000
36:
1.12 markus 37: /* Max len of agent socket */
38: #define MAX_SOCKET_NAME 100
39:
1.41 ! markus 40: /* default buffer for tcp-fwd-channel */
! 41: #define CHAN_WINDOW_DEFAULT (8*1024)
! 42: #define CHAN_PACKET_DEFAULT (CHAN_WINDOW_DEFAULT/2)
! 43:
1.27 markus 44: /*
45: * Pointer to an array containing all allocated channels. The array is
46: * dynamically extended as needed.
47: */
1.1 deraadt 48: static Channel *channels = NULL;
49:
1.27 markus 50: /*
51: * Size of the channel array. All slots of the array must always be
52: * initialized (at least the type field); unused slots are marked with type
53: * SSH_CHANNEL_FREE.
54: */
1.1 deraadt 55: static int channels_alloc = 0;
56:
1.27 markus 57: /*
58: * Maximum file descriptor value used in any of the channels. This is
59: * updated in channel_allocate.
60: */
1.1 deraadt 61: static int channel_max_fd_value = 0;
62:
1.12 markus 63: /* Name and directory of socket for authentication agent forwarding. */
1.1 deraadt 64: static char *channel_forwarded_auth_socket_name = NULL;
1.25 markus 65: static char *channel_forwarded_auth_socket_dir = NULL;
1.1 deraadt 66:
67: /* Saved X11 authentication protocol name. */
68: char *x11_saved_proto = NULL;
69:
70: /* Saved X11 authentication data. This is the real data. */
71: char *x11_saved_data = NULL;
72: unsigned int x11_saved_data_len = 0;
73:
1.27 markus 74: /*
75: * Fake X11 authentication data. This is what the server will be sending us;
76: * we should replace any occurrences of this by the real data.
77: */
1.1 deraadt 78: char *x11_fake_data = NULL;
79: unsigned int x11_fake_data_len;
80:
1.27 markus 81: /*
82: * Data structure for storing which hosts are permitted for forward requests.
83: * The local sides of any remote forwards are stored in this array to prevent
84: * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
85: * network (which might be behind a firewall).
86: */
1.25 markus 87: typedef struct {
1.41 ! markus 88: char *host_to_connect; /* Connect to 'host'. */
! 89: u_short port_to_connect; /* Connect to 'port'. */
! 90: u_short listen_port; /* Remote side should listen port number. */
1.1 deraadt 91: } ForwardPermission;
92:
93: /* List of all permitted host/port pairs to connect. */
94: static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
95: /* Number of permitted host/port pairs in the array. */
96: static int num_permitted_opens = 0;
1.27 markus 97: /*
98: * If this is true, all opens are permitted. This is the case on the server
99: * on which we have to trust the client anyway, and the user could do
100: * anything after logging in anyway.
101: */
1.1 deraadt 102: static int all_opens_permitted = 0;
103:
104: /* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */
105: static int have_hostname_in_open = 0;
106:
107: /* Sets specific protocol options. */
108:
1.25 markus 109: void
110: channel_set_options(int hostname_in_open)
1.1 deraadt 111: {
1.25 markus 112: have_hostname_in_open = hostname_in_open;
1.1 deraadt 113: }
114:
1.27 markus 115: /*
116: * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
117: * called by the server, because the user could connect to any port anyway,
118: * and the server has no way to know but to trust the client anyway.
119: */
1.1 deraadt 120:
1.25 markus 121: void
122: channel_permit_all_opens()
1.1 deraadt 123: {
1.25 markus 124: all_opens_permitted = 1;
1.1 deraadt 125: }
126:
1.41 ! markus 127: /* lookup channel by id */
! 128:
! 129: Channel *
! 130: channel_lookup(int id)
! 131: {
! 132: Channel *c;
! 133: if (id < 0 && id > channels_alloc) {
! 134: log("channel_lookup: %d: bad id", id);
! 135: return NULL;
! 136: }
! 137: c = &channels[id];
! 138: if (c->type == SSH_CHANNEL_FREE) {
! 139: log("channel_lookup: %d: bad id: channel free", id);
! 140: return NULL;
! 141: }
! 142: return c;
! 143: }
! 144:
1.27 markus 145: /*
146: * Allocate a new channel object and set its type and socket. This will cause
147: * remote_name to be freed.
148: */
1.1 deraadt 149:
1.25 markus 150: int
1.41 ! markus 151: channel_new(char *ctype, int type, int rfd, int wfd, int efd,
! 152: int window, int maxpack, int extended_usage, char *remote_name)
1.1 deraadt 153: {
1.25 markus 154: int i, found;
155: Channel *c;
1.1 deraadt 156:
1.25 markus 157: /* Update the maximum file descriptor value. */
1.41 ! markus 158: if (rfd > channel_max_fd_value)
! 159: channel_max_fd_value = rfd;
! 160: if (wfd > channel_max_fd_value)
! 161: channel_max_fd_value = wfd;
! 162: if (efd > channel_max_fd_value)
! 163: channel_max_fd_value = efd;
1.27 markus 164: /* XXX set close-on-exec -markus */
1.25 markus 165:
166: /* Do initial allocation if this is the first call. */
167: if (channels_alloc == 0) {
168: channels_alloc = 10;
169: channels = xmalloc(channels_alloc * sizeof(Channel));
170: for (i = 0; i < channels_alloc; i++)
171: channels[i].type = SSH_CHANNEL_FREE;
1.27 markus 172: /*
173: * Kludge: arrange a call to channel_stop_listening if we
174: * terminate with fatal().
175: */
1.25 markus 176: fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
177: }
178: /* Try to find a free slot where to put the new channel. */
179: for (found = -1, i = 0; i < channels_alloc; i++)
180: if (channels[i].type == SSH_CHANNEL_FREE) {
181: /* Found a free slot. */
182: found = i;
183: break;
184: }
185: if (found == -1) {
1.27 markus 186: /* There are no free slots. Take last+1 slot and expand the array. */
1.25 markus 187: found = channels_alloc;
188: channels_alloc += 10;
189: debug("channel: expanding %d", channels_alloc);
190: channels = xrealloc(channels, channels_alloc * sizeof(Channel));
191: for (i = found; i < channels_alloc; i++)
192: channels[i].type = SSH_CHANNEL_FREE;
193: }
194: /* Initialize and return new channel number. */
195: c = &channels[found];
196: buffer_init(&c->input);
197: buffer_init(&c->output);
1.41 ! markus 198: buffer_init(&c->extended);
1.25 markus 199: chan_init_iostates(c);
200: c->self = found;
201: c->type = type;
1.41 ! markus 202: c->ctype = ctype;
! 203: c->local_window = window;
! 204: c->local_window_max = window;
! 205: c->local_consumed = 0;
! 206: c->local_maxpacket = maxpack;
! 207: c->remote_window = 0;
! 208: c->remote_maxpacket = 0;
! 209: c->rfd = rfd;
! 210: c->wfd = wfd;
! 211: c->sock = (rfd == wfd) ? rfd : -1;
! 212: c->efd = efd;
! 213: c->extended_usage = extended_usage;
1.25 markus 214: c->remote_id = -1;
215: c->remote_name = remote_name;
1.41 ! markus 216: c->remote_window = 0;
! 217: c->remote_maxpacket = 0;
! 218: c->cb_fn = NULL;
! 219: c->cb_arg = NULL;
! 220: c->cb_event = 0;
! 221: c->dettach_user = NULL;
1.25 markus 222: debug("channel %d: new [%s]", found, remote_name);
223: return found;
1.1 deraadt 224: }
1.41 ! markus 225: int
! 226: channel_allocate(int type, int sock, char *remote_name)
! 227: {
! 228: return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name);
! 229: }
1.1 deraadt 230:
231: /* Free the channel and close its socket. */
232:
1.25 markus 233: void
1.41 ! markus 234: channel_free(int id)
1.1 deraadt 235: {
1.41 ! markus 236: Channel *c = channel_lookup(id);
! 237: if (c == NULL)
! 238: packet_disconnect("channel free: bad local channel %d", id);
! 239: debug("channel_free: channel %d: status: %s", id, channel_open_message());
1.25 markus 240: if (compat13)
1.41 ! markus 241: shutdown(c->sock, SHUT_RDWR);
! 242: buffer_free(&c->input);
! 243: buffer_free(&c->output);
! 244: buffer_free(&c->extended);
! 245: c->type = SSH_CHANNEL_FREE;
! 246: if (c->remote_name) {
! 247: xfree(c->remote_name);
! 248: c->remote_name = NULL;
1.25 markus 249: }
1.1 deraadt 250: }
251:
1.27 markus 252: /*
1.41 ! markus 253: * 'channel_pre*' are called just before select() to add any bits relevant to
! 254: * channels in the select bitmasks.
! 255: */
! 256: /*
! 257: * 'channel_post*': perform any appropriate operations for channels which
! 258: * have events pending.
1.27 markus 259: */
1.41 ! markus 260: typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
! 261: chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
! 262: chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
! 263:
! 264: void
! 265: channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
! 266: {
! 267: FD_SET(c->sock, readset);
! 268: }
! 269:
! 270: void
! 271: channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
! 272: {
! 273: if (buffer_len(&c->input) < packet_get_maxsize())
! 274: FD_SET(c->sock, readset);
! 275: if (buffer_len(&c->output) > 0)
! 276: FD_SET(c->sock, writeset);
! 277: }
1.1 deraadt 278:
1.41 ! markus 279: void
! 280: channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
! 281: {
! 282: /* test whether sockets are 'alive' for read/write */
! 283: if (c->istate == CHAN_INPUT_OPEN)
! 284: if (buffer_len(&c->input) < packet_get_maxsize())
! 285: FD_SET(c->sock, readset);
! 286: if (c->ostate == CHAN_OUTPUT_OPEN ||
! 287: c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
! 288: if (buffer_len(&c->output) > 0) {
! 289: FD_SET(c->sock, writeset);
! 290: } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
! 291: chan_obuf_empty(c);
! 292: }
! 293: }
! 294: }
! 295:
! 296: void
! 297: channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
! 298: {
! 299: if (buffer_len(&c->input) == 0) {
! 300: packet_start(SSH_MSG_CHANNEL_CLOSE);
! 301: packet_put_int(c->remote_id);
! 302: packet_send();
! 303: c->type = SSH_CHANNEL_CLOSED;
! 304: debug("Closing channel %d after input drain.", c->self);
! 305: }
! 306: }
! 307:
! 308: void
! 309: channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
! 310: {
! 311: if (buffer_len(&c->output) == 0)
! 312: channel_free(c->self);
! 313: else
! 314: FD_SET(c->sock, writeset);
! 315: }
! 316:
! 317: /*
! 318: * This is a special state for X11 authentication spoofing. An opened X11
! 319: * connection (when authentication spoofing is being done) remains in this
! 320: * state until the first packet has been completely read. The authentication
! 321: * data in that packet is then substituted by the real data if it matches the
! 322: * fake data, and the channel is put into normal mode.
! 323: */
! 324: int
! 325: x11_open_helper(Channel *c)
1.1 deraadt 326: {
1.25 markus 327: unsigned char *ucp;
328: unsigned int proto_len, data_len;
329:
1.41 ! markus 330: /* Check if the fixed size part of the packet is in buffer. */
! 331: if (buffer_len(&c->output) < 12)
! 332: return 0;
! 333:
! 334: /* Parse the lengths of variable-length fields. */
! 335: ucp = (unsigned char *) buffer_ptr(&c->output);
! 336: if (ucp[0] == 0x42) { /* Byte order MSB first. */
! 337: proto_len = 256 * ucp[6] + ucp[7];
! 338: data_len = 256 * ucp[8] + ucp[9];
! 339: } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
! 340: proto_len = ucp[6] + 256 * ucp[7];
! 341: data_len = ucp[8] + 256 * ucp[9];
! 342: } else {
! 343: debug("Initial X11 packet contains bad byte order byte: 0x%x",
! 344: ucp[0]);
! 345: return -1;
! 346: }
! 347:
! 348: /* Check if the whole packet is in buffer. */
! 349: if (buffer_len(&c->output) <
! 350: 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
! 351: return 0;
! 352:
! 353: /* Check if authentication protocol matches. */
! 354: if (proto_len != strlen(x11_saved_proto) ||
! 355: memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
! 356: debug("X11 connection uses different authentication protocol.");
! 357: return -1;
! 358: }
! 359: /* Check if authentication data matches our fake data. */
! 360: if (data_len != x11_fake_data_len ||
! 361: memcmp(ucp + 12 + ((proto_len + 3) & ~3),
! 362: x11_fake_data, x11_fake_data_len) != 0) {
! 363: debug("X11 auth data does not match fake data.");
! 364: return -1;
! 365: }
! 366: /* Check fake data length */
! 367: if (x11_fake_data_len != x11_saved_data_len) {
! 368: error("X11 fake_data_len %d != saved_data_len %d",
! 369: x11_fake_data_len, x11_saved_data_len);
! 370: return -1;
! 371: }
! 372: /*
! 373: * Received authentication protocol and data match
! 374: * our fake data. Substitute the fake data with real
! 375: * data.
! 376: */
! 377: memcpy(ucp + 12 + ((proto_len + 3) & ~3),
! 378: x11_saved_data, x11_saved_data_len);
! 379: return 1;
! 380: }
! 381:
! 382: void
! 383: channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
! 384: {
! 385: int ret = x11_open_helper(c);
! 386: if (ret == 1) {
! 387: /* Start normal processing for the channel. */
! 388: c->type = SSH_CHANNEL_OPEN;
! 389: } else if (ret == -1) {
! 390: /*
! 391: * We have received an X11 connection that has bad
! 392: * authentication information.
! 393: */
! 394: log("X11 connection rejected because of wrong authentication.\r\n");
! 395: buffer_clear(&c->input);
! 396: buffer_clear(&c->output);
! 397: close(c->sock);
! 398: c->sock = -1;
! 399: c->type = SSH_CHANNEL_CLOSED;
! 400: packet_start(SSH_MSG_CHANNEL_CLOSE);
! 401: packet_put_int(c->remote_id);
! 402: packet_send();
! 403: }
! 404: }
1.25 markus 405:
1.41 ! markus 406: void
! 407: channel_pre_x11_open_15(Channel *c, fd_set * readset, fd_set * writeset)
! 408: {
! 409: int ret = x11_open_helper(c);
! 410: if (ret == 1) {
! 411: c->type = SSH_CHANNEL_OPEN;
! 412: } else if (ret == -1) {
! 413: debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
! 414: chan_read_failed(c);
! 415: chan_write_failed(c);
! 416: debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
! 417: }
! 418: }
1.25 markus 419:
1.41 ! markus 420: /* This is our fake X11 server socket. */
! 421: void
! 422: channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
! 423: {
! 424: struct sockaddr addr;
! 425: int newsock, newch;
! 426: socklen_t addrlen;
! 427: char buf[16384], *remote_hostname;
1.25 markus 428:
1.41 ! markus 429: if (FD_ISSET(c->sock, readset)) {
! 430: debug("X11 connection requested.");
! 431: addrlen = sizeof(addr);
! 432: newsock = accept(c->sock, &addr, &addrlen);
! 433: if (newsock < 0) {
! 434: error("accept: %.100s", strerror(errno));
! 435: return;
! 436: }
! 437: remote_hostname = get_remote_hostname(newsock);
! 438: snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
! 439: remote_hostname, get_peer_port(newsock));
! 440: xfree(remote_hostname);
! 441: newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
! 442: xstrdup(buf));
! 443: packet_start(SSH_SMSG_X11_OPEN);
! 444: packet_put_int(newch);
! 445: if (have_hostname_in_open)
! 446: packet_put_string(buf, strlen(buf));
! 447: packet_send();
! 448: }
! 449: }
1.25 markus 450:
1.41 ! markus 451: /*
! 452: * This socket is listening for connections to a forwarded TCP/IP port.
! 453: */
! 454: void
! 455: channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
! 456: {
! 457: struct sockaddr addr;
! 458: int newsock, newch;
! 459: socklen_t addrlen;
! 460: char buf[1024], *remote_hostname;
! 461: int remote_port;
1.25 markus 462:
1.41 ! markus 463: if (FD_ISSET(c->sock, readset)) {
! 464: debug("Connection to port %d forwarding "
! 465: "to %.100s port %d requested.",
! 466: c->listening_port, c->path, c->host_port);
! 467: addrlen = sizeof(addr);
! 468: newsock = accept(c->sock, &addr, &addrlen);
! 469: if (newsock < 0) {
! 470: error("accept: %.100s", strerror(errno));
! 471: return;
! 472: }
! 473: remote_hostname = get_remote_hostname(newsock);
! 474: remote_port = get_peer_port(newsock);
! 475: snprintf(buf, sizeof buf,
! 476: "listen port %d for %.100s port %d, "
! 477: "connect from %.200s port %d",
! 478: c->listening_port, c->path, c->host_port,
! 479: remote_hostname, remote_port);
! 480: newch = channel_new("direct-tcpip",
! 481: SSH_CHANNEL_OPENING, newsock, newsock, -1,
! 482: c->local_window_max, c->local_maxpacket,
! 483: 0, xstrdup(buf));
! 484:
! 485: packet_start(SSH_MSG_PORT_OPEN);
! 486: packet_put_int(newch);
! 487: packet_put_string(c->path, strlen(c->path));
! 488: packet_put_int(c->host_port);
! 489: if (have_hostname_in_open) {
! 490: packet_put_string(buf, strlen(buf));
! 491: }
! 492: packet_send();
! 493: xfree(remote_hostname);
! 494: }
! 495: }
1.25 markus 496:
1.41 ! markus 497: /*
! 498: * This is the authentication agent socket listening for connections from
! 499: * clients.
! 500: */
! 501: void
! 502: channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
! 503: {
! 504: struct sockaddr addr;
! 505: int newsock, newch;
! 506: socklen_t addrlen;
1.25 markus 507:
1.41 ! markus 508: if (FD_ISSET(c->sock, readset)) {
! 509: addrlen = sizeof(addr);
! 510: newsock = accept(c->sock, &addr, &addrlen);
! 511: if (newsock < 0) {
! 512: error("accept from auth socket: %.100s", strerror(errno));
! 513: return;
! 514: }
! 515: newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
! 516: xstrdup("accepted auth socket"));
! 517: packet_start(SSH_SMSG_AGENT_OPEN);
! 518: packet_put_int(newch);
! 519: packet_send();
! 520: }
! 521: }
1.25 markus 522:
1.41 ! markus 523: int
! 524: channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
! 525: {
! 526: char buf[16*1024];
! 527: int len;
1.25 markus 528:
1.41 ! markus 529: if (c->rfd != -1 &&
! 530: FD_ISSET(c->rfd, readset)) {
! 531: len = read(c->rfd, buf, sizeof(buf));
! 532: if (len <= 0) {
! 533: debug("channel %d: read<0 rfd %d len %d",
! 534: c->self, c->rfd, len);
1.25 markus 535: if (compat13) {
1.41 ! markus 536: buffer_consume(&c->output, buffer_len(&c->output));
! 537: c->type = SSH_CHANNEL_INPUT_DRAINING;
! 538: debug("Channel %d status set to input draining.", c->self);
1.25 markus 539: } else {
1.41 ! markus 540: chan_read_failed(c);
1.25 markus 541: }
1.41 ! markus 542: return -1;
! 543: }
! 544: buffer_append(&c->input, buf, len);
! 545: }
! 546: return 1;
! 547: }
! 548: int
! 549: channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
! 550: {
! 551: int len;
1.25 markus 552:
1.41 ! markus 553: /* Send buffered output data to the socket. */
! 554: if (c->wfd != -1 &&
! 555: FD_ISSET(c->wfd, writeset) &&
! 556: buffer_len(&c->output) > 0) {
! 557: len = write(c->wfd, buffer_ptr(&c->output),
! 558: buffer_len(&c->output));
! 559: if (len <= 0) {
! 560: if (compat13) {
! 561: buffer_consume(&c->output, buffer_len(&c->output));
! 562: debug("Channel %d status set to input draining.", c->self);
! 563: c->type = SSH_CHANNEL_INPUT_DRAINING;
! 564: } else {
! 565: chan_write_failed(c);
! 566: }
! 567: return -1;
1.25 markus 568: }
1.41 ! markus 569: buffer_consume(&c->output, len);
1.1 deraadt 570: }
1.41 ! markus 571: return 1;
1.1 deraadt 572: }
573:
1.41 ! markus 574: void
! 575: channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
! 576: {
! 577: channel_handle_rfd(c, readset, writeset);
! 578: channel_handle_wfd(c, readset, writeset);
! 579: }
1.1 deraadt 580:
1.41 ! markus 581: void
! 582: channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1.1 deraadt 583: {
1.41 ! markus 584: int len;
! 585: /* Send buffered output data to the socket. */
! 586: if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
! 587: len = write(c->sock, buffer_ptr(&c->output),
! 588: buffer_len(&c->output));
! 589: if (len <= 0)
! 590: buffer_consume(&c->output, buffer_len(&c->output));
! 591: else
! 592: buffer_consume(&c->output, len);
! 593: }
! 594: }
1.25 markus 595:
1.41 ! markus 596: void
! 597: channel_handler_init_13(void)
! 598: {
! 599: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
! 600: channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
! 601: channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
! 602: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
! 603: channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
! 604: channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
! 605: channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1.25 markus 606:
1.41 ! markus 607: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
! 608: channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
! 609: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
! 610: channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
! 611: channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
! 612: }
1.25 markus 613:
1.41 ! markus 614: void
! 615: channel_handler_init_15(void)
! 616: {
! 617: channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
! 618: channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_15;
! 619: channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
! 620: channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
! 621: channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1.25 markus 622:
1.41 ! markus 623: channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
! 624: channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
! 625: channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
! 626: channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
! 627: }
1.27 markus 628:
1.41 ! markus 629: void
! 630: channel_handler_init(void)
! 631: {
! 632: int i;
! 633: for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
! 634: channel_pre[i] = NULL;
! 635: channel_post[i] = NULL;
! 636: }
! 637: if (compat13)
! 638: channel_handler_init_13();
! 639: else
! 640: channel_handler_init_15();
! 641: }
1.25 markus 642:
1.41 ! markus 643: void
! 644: channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
! 645: {
! 646: static int did_init = 0;
! 647: int i;
! 648: Channel *c;
1.25 markus 649:
1.41 ! markus 650: if (!did_init) {
! 651: channel_handler_init();
! 652: did_init = 1;
! 653: }
! 654: for (i = 0; i < channels_alloc; i++) {
! 655: c = &channels[i];
! 656: if (c->type == SSH_CHANNEL_FREE)
! 657: continue;
! 658: if (ftab[c->type] == NULL)
1.25 markus 659: continue;
1.41 ! markus 660: (*ftab[c->type])(c, readset, writeset);
! 661: chan_delete_if_full_closed(c);
1.1 deraadt 662: }
663: }
664:
1.41 ! markus 665: void
! 666: channel_prepare_select(fd_set * readset, fd_set * writeset)
! 667: {
! 668: channel_handler(channel_pre, readset, writeset);
! 669: }
! 670:
! 671: void
! 672: channel_after_select(fd_set * readset, fd_set * writeset)
! 673: {
! 674: channel_handler(channel_post, readset, writeset);
! 675: }
! 676:
1.1 deraadt 677: /* If there is data to send to the connection, send some of it now. */
678:
1.25 markus 679: void
680: channel_output_poll()
1.1 deraadt 681: {
1.25 markus 682: int len, i;
1.41 ! markus 683: Channel *c;
1.1 deraadt 684:
1.25 markus 685: for (i = 0; i < channels_alloc; i++) {
1.41 ! markus 686: c = &channels[i];
1.37 markus 687:
1.27 markus 688: /* We are only interested in channels that can have buffered incoming data. */
1.37 markus 689: if (compat13) {
1.41 ! markus 690: if (c->type != SSH_CHANNEL_OPEN &&
! 691: c->type != SSH_CHANNEL_INPUT_DRAINING)
1.37 markus 692: continue;
693: } else {
1.41 ! markus 694: if (c->type != SSH_CHANNEL_OPEN)
1.37 markus 695: continue;
1.41 ! markus 696: if (c->istate != CHAN_INPUT_OPEN &&
! 697: c->istate != CHAN_INPUT_WAIT_DRAIN)
1.37 markus 698: continue;
699: }
1.25 markus 700:
701: /* Get the amount of buffered data for this channel. */
1.41 ! markus 702: len = buffer_len(&c->input);
1.25 markus 703: if (len > 0) {
1.27 markus 704: /* Send some data for the other side over the secure connection. */
1.25 markus 705: if (packet_is_interactive()) {
706: if (len > 1024)
707: len = 512;
708: } else {
709: /* Keep the packets at reasonable size. */
1.40 markus 710: if (len > packet_get_maxsize())
1.34 markus 711: len = packet_get_maxsize()/2;
1.25 markus 712: }
1.41 ! markus 713: if (len > 0) {
! 714: packet_start(SSH_MSG_CHANNEL_DATA);
! 715: packet_put_int(c->remote_id);
! 716: packet_put_string(buffer_ptr(&c->input), len);
! 717: packet_send();
! 718: buffer_consume(&c->input, len);
! 719: c->remote_window -= len;
! 720: debug("channel %d: send data len %d", c->self, len);
! 721: }
! 722: } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1.25 markus 723: if (compat13)
724: fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1.27 markus 725: /*
726: * input-buffer is empty and read-socket shutdown:
727: * tell peer, that we will not send more data: send IEOF
728: */
1.41 ! markus 729: chan_ibuf_empty(c);
1.25 markus 730: }
731: }
1.1 deraadt 732: }
733:
1.27 markus 734: /*
735: * This is called when a packet of type CHANNEL_DATA has just been received.
736: * The message type has already been consumed, but channel number and data is
737: * still there.
738: */
1.1 deraadt 739:
1.25 markus 740: void
1.41 ! markus 741: channel_input_data(int type, int plen)
1.1 deraadt 742: {
1.37 markus 743: int id;
1.25 markus 744: char *data;
745: unsigned int data_len;
1.41 ! markus 746: Channel *c;
1.25 markus 747:
748: /* Get the channel number and verify it. */
1.37 markus 749: id = packet_get_int();
1.41 ! markus 750: c = channel_lookup(id);
! 751: if (c == NULL)
1.37 markus 752: packet_disconnect("Received data for nonexistent channel %d.", id);
1.25 markus 753:
754: /* Ignore any data for non-open channels (might happen on close) */
1.41 ! markus 755: if (c->type != SSH_CHANNEL_OPEN &&
! 756: c->type != SSH_CHANNEL_X11_OPEN)
1.37 markus 757: return;
758:
759: /* same for protocol 1.5 if output end is no longer open */
1.41 ! markus 760: if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1.25 markus 761: return;
762:
763: /* Get the data. */
764: data = packet_get_string(&data_len);
1.41 ! markus 765:
! 766: packet_integrity_check(plen, 4 + 4 + data_len, SSH_MSG_CHANNEL_DATA);
! 767: buffer_append(&c->output, data, data_len);
1.25 markus 768: xfree(data);
1.1 deraadt 769: }
770:
1.27 markus 771: /*
772: * Returns true if no channel has too much buffered data, and false if one or
773: * more channel is overfull.
774: */
1.1 deraadt 775:
1.25 markus 776: int
777: channel_not_very_much_buffered_data()
1.1 deraadt 778: {
1.25 markus 779: unsigned int i;
1.41 ! markus 780: Channel *c;
1.25 markus 781:
782: for (i = 0; i < channels_alloc; i++) {
1.41 ! markus 783: c = &channels[i];
! 784: if (c->type == SSH_CHANNEL_OPEN) {
! 785: if (buffer_len(&c->input) > packet_get_maxsize()) {
! 786: debug("channel %d: big input buffer %d",
! 787: c->self, buffer_len(&c->input));
1.25 markus 788: return 0;
1.41 ! markus 789: }
! 790: if (buffer_len(&c->output) > packet_get_maxsize()) {
! 791: debug("channel %d: big output buffer %d",
! 792: c->self, buffer_len(&c->output));
1.25 markus 793: return 0;
1.41 ! markus 794: }
1.25 markus 795: }
1.1 deraadt 796: }
1.25 markus 797: return 1;
1.1 deraadt 798: }
799:
1.41 ! markus 800: void
! 801: channel_input_ieof(int type, int plen)
! 802: {
! 803: int id;
! 804: Channel *c;
! 805:
! 806: packet_integrity_check(plen, 4, type);
! 807:
! 808: id = packet_get_int();
! 809: c = channel_lookup(id);
! 810: if (c == NULL)
! 811: packet_disconnect("Received ieof for nonexistent channel %d.", id);
! 812: chan_rcvd_ieof(c);
! 813: }
1.1 deraadt 814:
1.25 markus 815: void
1.41 ! markus 816: channel_input_close(int type, int plen)
1.1 deraadt 817: {
1.41 ! markus 818: int id;
! 819: Channel *c;
1.1 deraadt 820:
1.41 ! markus 821: packet_integrity_check(plen, 4, type);
! 822:
! 823: id = packet_get_int();
! 824: c = channel_lookup(id);
! 825: if (c == NULL)
! 826: packet_disconnect("Received close for nonexistent channel %d.", id);
1.27 markus 827:
828: /*
829: * Send a confirmation that we have closed the channel and no more
830: * data is coming for it.
831: */
1.25 markus 832: packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1.41 ! markus 833: packet_put_int(c->remote_id);
1.25 markus 834: packet_send();
835:
1.27 markus 836: /*
837: * If the channel is in closed state, we have sent a close request,
838: * and the other side will eventually respond with a confirmation.
839: * Thus, we cannot free the channel here, because then there would be
840: * no-one to receive the confirmation. The channel gets freed when
841: * the confirmation arrives.
842: */
1.41 ! markus 843: if (c->type != SSH_CHANNEL_CLOSED) {
1.27 markus 844: /*
845: * Not a closed channel - mark it as draining, which will
846: * cause it to be freed later.
847: */
1.41 ! markus 848: buffer_consume(&c->input, buffer_len(&c->input));
! 849: c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1.25 markus 850: }
1.1 deraadt 851: }
852:
1.41 ! markus 853: /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
! 854: void
! 855: channel_input_oclose(int type, int plen)
! 856: {
! 857: int id = packet_get_int();
! 858: Channel *c = channel_lookup(id);
! 859: packet_integrity_check(plen, 4, type);
! 860: if (c == NULL)
! 861: packet_disconnect("Received oclose for nonexistent channel %d.", id);
! 862: chan_rcvd_oclose(c);
! 863: }
1.1 deraadt 864:
1.25 markus 865: void
1.41 ! markus 866: channel_input_close_confirmation(int type, int plen)
1.1 deraadt 867: {
1.41 ! markus 868: int id = packet_get_int();
! 869: Channel *c = channel_lookup(id);
1.1 deraadt 870:
1.41 ! markus 871: if (c == NULL)
! 872: packet_disconnect("Received close confirmation for "
! 873: "out-of-range channel %d.", id);
! 874: if (c->type != SSH_CHANNEL_CLOSED)
! 875: packet_disconnect("Received close confirmation for "
! 876: "non-closed channel %d (type %d).", id, c->type);
! 877: channel_free(c->self);
1.1 deraadt 878: }
879:
1.25 markus 880: void
1.41 ! markus 881: channel_input_open_confirmation(int type, int plen)
1.1 deraadt 882: {
1.41 ! markus 883: int id, remote_id;
! 884: Channel *c;
1.1 deraadt 885:
1.41 ! markus 886: packet_integrity_check(plen, 4 + 4, type);
1.25 markus 887:
1.41 ! markus 888: id = packet_get_int();
! 889: c = channel_lookup(id);
1.25 markus 890:
1.41 ! markus 891: if (c==NULL || c->type != SSH_CHANNEL_OPENING)
! 892: packet_disconnect("Received open confirmation for "
! 893: "non-opening channel %d.", id);
! 894: remote_id = packet_get_int();
1.27 markus 895: /* Record the remote channel number and mark that the channel is now open. */
1.41 ! markus 896: c->remote_id = remote_id;
! 897: c->type = SSH_CHANNEL_OPEN;
1.1 deraadt 898: }
899:
1.25 markus 900: void
1.41 ! markus 901: channel_input_open_failure(int type, int plen)
1.1 deraadt 902: {
1.41 ! markus 903: int id;
! 904: Channel *c;
! 905:
! 906: packet_integrity_check(plen, 4, type);
! 907:
! 908: id = packet_get_int();
! 909: c = channel_lookup(id);
1.25 markus 910:
1.41 ! markus 911: if (c==NULL || c->type != SSH_CHANNEL_OPENING)
! 912: packet_disconnect("Received open failure for "
! 913: "non-opening channel %d.", id);
1.1 deraadt 914:
1.25 markus 915: /* Free the channel. This will also close the socket. */
1.41 ! markus 916: channel_free(id);
1.1 deraadt 917: }
918:
1.27 markus 919: /*
920: * Stops listening for channels, and removes any unix domain sockets that we
921: * might have.
922: */
1.1 deraadt 923:
1.25 markus 924: void
925: channel_stop_listening()
1.1 deraadt 926: {
1.25 markus 927: int i;
928: for (i = 0; i < channels_alloc; i++) {
929: switch (channels[i].type) {
930: case SSH_CHANNEL_AUTH_SOCKET:
931: close(channels[i].sock);
932: remove(channels[i].path);
933: channel_free(i);
934: break;
935: case SSH_CHANNEL_PORT_LISTENER:
936: case SSH_CHANNEL_X11_LISTENER:
937: close(channels[i].sock);
938: channel_free(i);
939: break;
940: default:
941: break;
942: }
1.1 deraadt 943: }
944: }
945:
1.27 markus 946: /*
947: * Closes the sockets of all channels. This is used to close extra file
948: * descriptors after a fork.
949: */
1.1 deraadt 950:
1.25 markus 951: void
952: channel_close_all()
1.1 deraadt 953: {
1.25 markus 954: int i;
955: for (i = 0; i < channels_alloc; i++) {
956: if (channels[i].type != SSH_CHANNEL_FREE)
957: close(channels[i].sock);
958: }
1.1 deraadt 959: }
960:
961: /* Returns the maximum file descriptor number used by the channels. */
962:
1.25 markus 963: int
964: channel_max_fd()
1.1 deraadt 965: {
1.25 markus 966: return channel_max_fd_value;
1.1 deraadt 967: }
968:
969: /* Returns true if any channel is still open. */
970:
1.25 markus 971: int
972: channel_still_open()
1.1 deraadt 973: {
1.25 markus 974: unsigned int i;
975: for (i = 0; i < channels_alloc; i++)
976: switch (channels[i].type) {
977: case SSH_CHANNEL_FREE:
978: case SSH_CHANNEL_X11_LISTENER:
979: case SSH_CHANNEL_PORT_LISTENER:
980: case SSH_CHANNEL_CLOSED:
981: case SSH_CHANNEL_AUTH_SOCKET:
982: continue;
983: case SSH_CHANNEL_OPENING:
984: case SSH_CHANNEL_OPEN:
985: case SSH_CHANNEL_X11_OPEN:
986: return 1;
987: case SSH_CHANNEL_INPUT_DRAINING:
988: case SSH_CHANNEL_OUTPUT_DRAINING:
989: if (!compat13)
990: fatal("cannot happen: OUT_DRAIN");
991: return 1;
992: default:
993: fatal("channel_still_open: bad channel type %d", channels[i].type);
994: /* NOTREACHED */
995: }
996: return 0;
1.1 deraadt 997: }
998:
1.27 markus 999: /*
1000: * Returns a message describing the currently open forwarded connections,
1001: * suitable for sending to the client. The message contains crlf pairs for
1002: * newlines.
1003: */
1.1 deraadt 1004:
1.25 markus 1005: char *
1006: channel_open_message()
1.1 deraadt 1007: {
1.25 markus 1008: Buffer buffer;
1009: int i;
1010: char buf[512], *cp;
1011:
1012: buffer_init(&buffer);
1013: snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1.1 deraadt 1014: buffer_append(&buffer, buf, strlen(buf));
1.25 markus 1015: for (i = 0; i < channels_alloc; i++) {
1016: Channel *c = &channels[i];
1017: switch (c->type) {
1018: case SSH_CHANNEL_FREE:
1019: case SSH_CHANNEL_X11_LISTENER:
1020: case SSH_CHANNEL_PORT_LISTENER:
1021: case SSH_CHANNEL_CLOSED:
1022: case SSH_CHANNEL_AUTH_SOCKET:
1023: continue;
1024: case SSH_CHANNEL_OPENING:
1025: case SSH_CHANNEL_OPEN:
1026: case SSH_CHANNEL_X11_OPEN:
1027: case SSH_CHANNEL_INPUT_DRAINING:
1028: case SSH_CHANNEL_OUTPUT_DRAINING:
1.41 ! markus 1029: snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1.37 markus 1030: c->self, c->remote_name,
1031: c->type, c->remote_id,
1032: c->istate, buffer_len(&c->input),
1.41 ! markus 1033: c->ostate, buffer_len(&c->output),
! 1034: c->rfd, c->wfd);
1.25 markus 1035: buffer_append(&buffer, buf, strlen(buf));
1036: continue;
1037: default:
1.41 ! markus 1038: fatal("channel_open_message: bad channel type %d", c->type);
1.25 markus 1039: /* NOTREACHED */
1040: }
1041: }
1042: buffer_append(&buffer, "\0", 1);
1043: cp = xstrdup(buffer_ptr(&buffer));
1044: buffer_free(&buffer);
1045: return cp;
1.1 deraadt 1046: }
1047:
1.27 markus 1048: /*
1049: * Initiate forwarding of connections to local port "port" through the secure
1050: * channel to host:port from remote side.
1051: */
1.1 deraadt 1052:
1.25 markus 1053: void
1.31 markus 1054: channel_request_local_forwarding(u_short port, const char *host,
1.33 markus 1055: u_short host_port, int gateway_ports)
1.25 markus 1056: {
1.35 markus 1057: int success, ch, sock, on = 1;
1058: struct addrinfo hints, *ai, *aitop;
1059: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1.28 markus 1060: struct linger linger;
1.25 markus 1061:
1062: if (strlen(host) > sizeof(channels[0].path) - 1)
1063: packet_disconnect("Forward host name too long.");
1064:
1.28 markus 1065: /*
1.35 markus 1066: * getaddrinfo returns a loopback address if the hostname is
1067: * set to NULL and hints.ai_flags is not AI_PASSIVE
1.28 markus 1068: */
1.35 markus 1069: memset(&hints, 0, sizeof(hints));
1070: hints.ai_family = IPv4or6;
1071: hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1072: hints.ai_socktype = SOCK_STREAM;
1073: snprintf(strport, sizeof strport, "%d", port);
1074: if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1075: packet_disconnect("getaddrinfo: fatal error");
1076:
1077: success = 0;
1078: for (ai = aitop; ai; ai = ai->ai_next) {
1079: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1080: continue;
1081: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1082: strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1083: error("channel_request_local_forwarding: getnameinfo failed");
1084: continue;
1085: }
1086: /* Create a port to listen for the host. */
1087: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1088: if (sock < 0) {
1089: /* this is no error since kernel may not support ipv6 */
1090: verbose("socket: %.100s", strerror(errno));
1091: continue;
1092: }
1093: /*
1094: * Set socket options. We would like the socket to disappear
1095: * as soon as it has been closed for whatever reason.
1096: */
1097: setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1098: linger.l_onoff = 1;
1099: linger.l_linger = 5;
1100: setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1101: debug("Local forwarding listening on %s port %s.", ntop, strport);
1102:
1103: /* Bind the socket to the address. */
1104: if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1105: /* address can be in use ipv6 address is already bound */
1106: verbose("bind: %.100s", strerror(errno));
1107: close(sock);
1108: continue;
1109: }
1110: /* Start listening for connections on the socket. */
1111: if (listen(sock, 5) < 0) {
1112: error("listen: %.100s", strerror(errno));
1113: close(sock);
1114: continue;
1115: }
1116: /* Allocate a channel number for the socket. */
1.41 ! markus 1117: ch = channel_new(
! 1118: "port listener", SSH_CHANNEL_PORT_LISTENER,
! 1119: sock, sock, -1,
! 1120: CHAN_WINDOW_DEFAULT, CHAN_PACKET_DEFAULT,
! 1121: 0, xstrdup("port listener"));
1.35 markus 1122: strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
1123: channels[ch].host_port = host_port;
1124: channels[ch].listening_port = port;
1125: success = 1;
1126: }
1127: if (success == 0)
1128: packet_disconnect("cannot listen port: %d", port);
1129: freeaddrinfo(aitop);
1.25 markus 1130: }
1.1 deraadt 1131:
1.27 markus 1132: /*
1133: * Initiate forwarding of connections to port "port" on remote host through
1134: * the secure channel to host:port from local side.
1135: */
1.1 deraadt 1136:
1.25 markus 1137: void
1.41 ! markus 1138: channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect,
! 1139: u_short port_to_connect)
1.25 markus 1140: {
1141: int payload_len;
1142: /* Record locally that connection to this host/port is permitted. */
1143: if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1144: fatal("channel_request_remote_forwarding: too many forwards");
1145:
1.41 ! markus 1146: permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
! 1147: permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
! 1148: permitted_opens[num_permitted_opens].listen_port = listen_port;
1.25 markus 1149: num_permitted_opens++;
1150:
1151: /* Send the forward request to the remote side. */
1152: packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
1.41 ! markus 1153: packet_put_int(port_to_connect);
! 1154: packet_put_string(host_to_connect, strlen(host_to_connect));
! 1155: packet_put_int(listen_port);
1.25 markus 1156: packet_send();
1157: packet_write_wait();
1.27 markus 1158: /*
1159: * Wait for response from the remote side. It will send a disconnect
1160: * message on failure, and we will never see it here.
1161: */
1.25 markus 1162: packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
1.1 deraadt 1163: }
1164:
1.27 markus 1165: /*
1166: * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1167: * listening for the port, and sends back a success reply (or disconnect
1168: * message if there was an error). This never returns if there was an error.
1169: */
1.1 deraadt 1170:
1.25 markus 1171: void
1172: channel_input_port_forward_request(int is_root)
1.1 deraadt 1173: {
1.31 markus 1174: u_short port, host_port;
1.25 markus 1175: char *hostname;
1.1 deraadt 1176:
1.25 markus 1177: /* Get arguments from the packet. */
1178: port = packet_get_int();
1179: hostname = packet_get_string(NULL);
1180: host_port = packet_get_int();
1181:
1.27 markus 1182: /*
1183: * Check that an unprivileged user is not trying to forward a
1184: * privileged port.
1185: */
1.25 markus 1186: if (port < IPPORT_RESERVED && !is_root)
1187: packet_disconnect("Requested forwarding of port %d but user is not root.",
1188: port);
1.33 markus 1189: /*
1190: * Initiate forwarding,
1191: * bind port to localhost only (gateway ports == 0).
1192: */
1193: channel_request_local_forwarding(port, hostname, host_port, 0);
1.25 markus 1194:
1195: /* Free the argument string. */
1196: xfree(hostname);
1.1 deraadt 1197: }
1198:
1.41 ! markus 1199: /* XXX move to aux.c */
! 1200: int
! 1201: channel_connect_to(const char *host, u_short host_port)
! 1202: {
! 1203: struct addrinfo hints, *ai, *aitop;
! 1204: char ntop[NI_MAXHOST], strport[NI_MAXSERV];
! 1205: int gaierr;
! 1206: int sock = -1;
! 1207:
! 1208: memset(&hints, 0, sizeof(hints));
! 1209: hints.ai_family = IPv4or6;
! 1210: hints.ai_socktype = SOCK_STREAM;
! 1211: snprintf(strport, sizeof strport, "%d", host_port);
! 1212: if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
! 1213: error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
! 1214: return -1;
! 1215: }
! 1216: for (ai = aitop; ai; ai = ai->ai_next) {
! 1217: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
! 1218: continue;
! 1219: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
! 1220: strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
! 1221: error("channel_connect_to: getnameinfo failed");
! 1222: continue;
! 1223: }
! 1224: /* Create the socket. */
! 1225: sock = socket(ai->ai_family, SOCK_STREAM, 0);
! 1226: if (sock < 0) {
! 1227: error("socket: %.100s", strerror(errno));
! 1228: continue;
! 1229: }
! 1230: /* Connect to the host/port. */
! 1231: if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
! 1232: error("connect %.100s port %s: %.100s", ntop, strport,
! 1233: strerror(errno));
! 1234: close(sock);
! 1235: continue; /* fail -- try next */
! 1236: }
! 1237: break; /* success */
! 1238:
! 1239: }
! 1240: freeaddrinfo(aitop);
! 1241: if (!ai) {
! 1242: error("connect %.100s port %d: failed.", host, host_port);
! 1243: return -1;
! 1244: }
! 1245: /* success */
! 1246: return sock;
! 1247: }
1.27 markus 1248: /*
1249: * This is called after receiving PORT_OPEN message. This attempts to
1250: * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
1251: * or CHANNEL_OPEN_FAILURE.
1252: */
1.1 deraadt 1253:
1.25 markus 1254: void
1.41 ! markus 1255: channel_input_port_open(int type, int plen)
1.1 deraadt 1256: {
1.31 markus 1257: u_short host_port;
1.25 markus 1258: char *host, *originator_string;
1.41 ! markus 1259: int remote_channel, sock = -1, newch, i, denied;
1.39 markus 1260: unsigned int host_len, originator_len;
1.25 markus 1261:
1262: /* Get remote channel number. */
1263: remote_channel = packet_get_int();
1264:
1265: /* Get host name to connect to. */
1266: host = packet_get_string(&host_len);
1267:
1268: /* Get port to connect to. */
1269: host_port = packet_get_int();
1270:
1271: /* Get remote originator name. */
1.29 markus 1272: if (have_hostname_in_open) {
1.25 markus 1273: originator_string = packet_get_string(&originator_len);
1.29 markus 1274: originator_len += 4; /* size of packet_int */
1275: } else {
1.25 markus 1276: originator_string = xstrdup("unknown (remote did not supply name)");
1.29 markus 1277: originator_len = 0; /* no originator supplied */
1278: }
1.25 markus 1279:
1.41 ! markus 1280: packet_integrity_check(plen,
! 1281: 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
1.25 markus 1282:
1283: /* Check if opening that port is permitted. */
1.41 ! markus 1284: denied = 0;
1.25 markus 1285: if (!all_opens_permitted) {
1286: /* Go trough all permitted ports. */
1287: for (i = 0; i < num_permitted_opens; i++)
1.41 ! markus 1288: if (permitted_opens[i].port_to_connect == host_port &&
! 1289: strcmp(permitted_opens[i].host_to_connect, host) == 0)
1.25 markus 1290: break;
1291:
1292: /* Check if we found the requested port among those permitted. */
1293: if (i >= num_permitted_opens) {
1294: /* The port is not permitted. */
1295: log("Received request to connect to %.100s:%d, but the request was denied.",
1296: host, host_port);
1.41 ! markus 1297: denied = 1;
1.25 markus 1298: }
1299: }
1.41 ! markus 1300: sock = denied ? -1 : channel_connect_to(host, host_port);
! 1301: if (sock > 0) {
! 1302: /* Allocate a channel for this connection. */
! 1303: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
! 1304: channels[newch].remote_id = remote_channel;
! 1305:
! 1306: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
! 1307: packet_put_int(remote_channel);
! 1308: packet_put_int(newch);
! 1309: packet_send();
! 1310: } else {
! 1311: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
! 1312: packet_put_int(remote_channel);
! 1313: packet_send();
1.25 markus 1314: }
1315: xfree(host);
1.1 deraadt 1316: }
1317:
1.27 markus 1318: /*
1319: * Creates an internet domain socket for listening for X11 connections.
1320: * Returns a suitable value for the DISPLAY variable, or NULL if an error
1321: * occurs.
1322: */
1.1 deraadt 1323:
1.35 markus 1324: #define NUM_SOCKS 10
1325:
1.25 markus 1326: char *
1.33 markus 1327: x11_create_display_inet(int screen_number, int x11_display_offset)
1.1 deraadt 1328: {
1.31 markus 1329: int display_number, sock;
1330: u_short port;
1.35 markus 1331: struct addrinfo hints, *ai, *aitop;
1332: char strport[NI_MAXSERV];
1333: int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
1334: char display[512];
1.25 markus 1335: char hostname[MAXHOSTNAMELEN];
1336:
1.33 markus 1337: for (display_number = x11_display_offset;
1.25 markus 1338: display_number < MAX_DISPLAYS;
1339: display_number++) {
1340: port = 6000 + display_number;
1.35 markus 1341: memset(&hints, 0, sizeof(hints));
1342: hints.ai_family = IPv4or6;
1.36 markus 1343: hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
1.35 markus 1344: hints.ai_socktype = SOCK_STREAM;
1345: snprintf(strport, sizeof strport, "%d", port);
1346: if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
1347: error("getaddrinfo: %.100s", gai_strerror(gaierr));
1.25 markus 1348: return NULL;
1349: }
1.35 markus 1350: for (ai = aitop; ai; ai = ai->ai_next) {
1351: if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1352: continue;
1353: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1354: if (sock < 0) {
1355: error("socket: %.100s", strerror(errno));
1356: return NULL;
1357: }
1358: if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1359: debug("bind port %d: %.100s", port, strerror(errno));
1360: shutdown(sock, SHUT_RDWR);
1361: close(sock);
1362: for (n = 0; n < num_socks; n++) {
1363: shutdown(socks[n], SHUT_RDWR);
1364: close(socks[n]);
1365: }
1366: num_socks = 0;
1367: break;
1368: }
1369: socks[num_socks++] = sock;
1370: if (num_socks == NUM_SOCKS)
1371: break;
1.25 markus 1372: }
1.35 markus 1373: if (num_socks > 0)
1374: break;
1.25 markus 1375: }
1376: if (display_number >= MAX_DISPLAYS) {
1377: error("Failed to allocate internet-domain X11 display socket.");
1378: return NULL;
1379: }
1380: /* Start listening for connections on the socket. */
1.35 markus 1381: for (n = 0; n < num_socks; n++) {
1382: sock = socks[n];
1383: if (listen(sock, 5) < 0) {
1384: error("listen: %.100s", strerror(errno));
1385: shutdown(sock, SHUT_RDWR);
1386: close(sock);
1387: return NULL;
1388: }
1.25 markus 1389: }
1.35 markus 1390:
1.25 markus 1391: /* Set up a suitable value for the DISPLAY variable. */
1392: if (gethostname(hostname, sizeof(hostname)) < 0)
1393: fatal("gethostname: %.100s", strerror(errno));
1.35 markus 1394: snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1.25 markus 1395: display_number, screen_number);
1396:
1.35 markus 1397: /* Allocate a channel for each socket. */
1398: for (n = 0; n < num_socks; n++) {
1399: sock = socks[n];
1400: (void) channel_allocate(SSH_CHANNEL_X11_LISTENER, sock,
1401: xstrdup("X11 inet listener"));
1402: }
1.1 deraadt 1403:
1.25 markus 1404: /* Return a suitable value for the DISPLAY environment variable. */
1.35 markus 1405: return xstrdup(display);
1.1 deraadt 1406: }
1407:
1408: #ifndef X_UNIX_PATH
1409: #define X_UNIX_PATH "/tmp/.X11-unix/X"
1410: #endif
1411:
1412: static
1413: int
1.30 deraadt 1414: connect_local_xsocket(unsigned int dnr)
1.1 deraadt 1415: {
1.25 markus 1416: static const char *const x_sockets[] = {
1417: X_UNIX_PATH "%u",
1418: "/var/X/.X11-unix/X" "%u",
1419: "/usr/spool/sockets/X11/" "%u",
1420: NULL
1421: };
1422: int sock;
1423: struct sockaddr_un addr;
1424: const char *const * path;
1425:
1426: for (path = x_sockets; *path; ++path) {
1427: sock = socket(AF_UNIX, SOCK_STREAM, 0);
1428: if (sock < 0)
1429: error("socket: %.100s", strerror(errno));
1430: memset(&addr, 0, sizeof(addr));
1431: addr.sun_family = AF_UNIX;
1432: snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
1433: if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
1434: return sock;
1435: close(sock);
1436: }
1437: error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
1438: return -1;
1.1 deraadt 1439: }
1440:
1441:
1.27 markus 1442: /*
1443: * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
1444: * the remote channel number. We should do whatever we want, and respond
1445: * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
1446: */
1.1 deraadt 1447:
1.25 markus 1448: void
1.41 ! markus 1449: x11_input_open(int type, int plen)
1.1 deraadt 1450: {
1.35 markus 1451: int remote_channel, display_number, sock = 0, newch;
1.25 markus 1452: const char *display;
1453: char buf[1024], *cp, *remote_host;
1.39 markus 1454: unsigned int remote_len;
1.35 markus 1455: struct addrinfo hints, *ai, *aitop;
1456: char strport[NI_MAXSERV];
1457: int gaierr;
1.25 markus 1458:
1459: /* Get remote channel number. */
1460: remote_channel = packet_get_int();
1461:
1462: /* Get remote originator name. */
1.29 markus 1463: if (have_hostname_in_open) {
1.25 markus 1464: remote_host = packet_get_string(&remote_len);
1.29 markus 1465: remote_len += 4;
1466: } else {
1.25 markus 1467: remote_host = xstrdup("unknown (remote did not supply name)");
1.29 markus 1468: remote_len = 0;
1469: }
1.25 markus 1470:
1471: debug("Received X11 open request.");
1.41 ! markus 1472: packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
1.25 markus 1473:
1474: /* Try to open a socket for the local X server. */
1475: display = getenv("DISPLAY");
1476: if (!display) {
1477: error("DISPLAY not set.");
1478: goto fail;
1479: }
1.27 markus 1480: /*
1481: * Now we decode the value of the DISPLAY variable and make a
1482: * connection to the real X server.
1483: */
1484:
1485: /*
1486: * Check if it is a unix domain socket. Unix domain displays are in
1487: * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
1488: */
1.25 markus 1489: if (strncmp(display, "unix:", 5) == 0 ||
1490: display[0] == ':') {
1491: /* Connect to the unix domain socket. */
1492: if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
1493: error("Could not parse display number from DISPLAY: %.100s",
1494: display);
1495: goto fail;
1496: }
1497: /* Create a socket. */
1498: sock = connect_local_xsocket(display_number);
1499: if (sock < 0)
1500: goto fail;
1501:
1502: /* OK, we now have a connection to the display. */
1503: goto success;
1504: }
1.27 markus 1505: /*
1506: * Connect to an inet socket. The DISPLAY value is supposedly
1507: * hostname:d[.s], where hostname may also be numeric IP address.
1508: */
1.25 markus 1509: strncpy(buf, display, sizeof(buf));
1510: buf[sizeof(buf) - 1] = 0;
1511: cp = strchr(buf, ':');
1512: if (!cp) {
1513: error("Could not find ':' in DISPLAY: %.100s", display);
1514: goto fail;
1515: }
1516: *cp = 0;
1.27 markus 1517: /* buf now contains the host name. But first we parse the display number. */
1.25 markus 1518: if (sscanf(cp + 1, "%d", &display_number) != 1) {
1519: error("Could not parse display number from DISPLAY: %.100s",
1520: display);
1521: goto fail;
1522: }
1.35 markus 1523:
1524: /* Look up the host address */
1525: memset(&hints, 0, sizeof(hints));
1526: hints.ai_family = IPv4or6;
1527: hints.ai_socktype = SOCK_STREAM;
1528: snprintf(strport, sizeof strport, "%d", 6000 + display_number);
1529: if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
1530: error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
1.25 markus 1531: goto fail;
1532: }
1.35 markus 1533: for (ai = aitop; ai; ai = ai->ai_next) {
1534: /* Create a socket. */
1535: sock = socket(ai->ai_family, SOCK_STREAM, 0);
1536: if (sock < 0) {
1537: debug("socket: %.100s", strerror(errno));
1.41 ! markus 1538: continue;
! 1539: }
! 1540: /* Connect it to the display. */
! 1541: if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
! 1542: debug("connect %.100s port %d: %.100s", buf,
! 1543: 6000 + display_number, strerror(errno));
! 1544: close(sock);
! 1545: continue;
! 1546: }
! 1547: /* Success */
! 1548: break;
1.35 markus 1549: }
1550: freeaddrinfo(aitop);
1551: if (!ai) {
1552: error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
1553: strerror(errno));
1.25 markus 1554: goto fail;
1555: }
1556: success:
1557: /* We have successfully obtained a connection to the real X display. */
1558:
1559: /* Allocate a channel for this connection. */
1560: if (x11_saved_proto == NULL)
1561: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, remote_host);
1562: else
1563: newch = channel_allocate(SSH_CHANNEL_X11_OPEN, sock, remote_host);
1564: channels[newch].remote_id = remote_channel;
1565:
1566: /* Send a confirmation to the remote host. */
1567: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1568: packet_put_int(remote_channel);
1569: packet_put_int(newch);
1570: packet_send();
1571:
1572: return;
1573:
1574: fail:
1575: /* Send refusal to the remote host. */
1576: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1577: packet_put_int(remote_channel);
1578: packet_send();
1.1 deraadt 1579: }
1580:
1.27 markus 1581: /*
1582: * Requests forwarding of X11 connections, generates fake authentication
1583: * data, and enables authentication spoofing.
1584: */
1.1 deraadt 1585:
1.25 markus 1586: void
1587: x11_request_forwarding_with_spoofing(const char *proto, const char *data)
1.1 deraadt 1588: {
1.25 markus 1589: unsigned int data_len = (unsigned int) strlen(data) / 2;
1590: unsigned int i, value;
1591: char *new_data;
1592: int screen_number;
1593: const char *cp;
1594: u_int32_t rand = 0;
1595:
1596: cp = getenv("DISPLAY");
1597: if (cp)
1598: cp = strchr(cp, ':');
1599: if (cp)
1600: cp = strchr(cp, '.');
1601: if (cp)
1602: screen_number = atoi(cp + 1);
1603: else
1604: screen_number = 0;
1605:
1606: /* Save protocol name. */
1607: x11_saved_proto = xstrdup(proto);
1608:
1.27 markus 1609: /*
1610: * Extract real authentication data and generate fake data of the
1611: * same length.
1612: */
1.25 markus 1613: x11_saved_data = xmalloc(data_len);
1614: x11_fake_data = xmalloc(data_len);
1615: for (i = 0; i < data_len; i++) {
1616: if (sscanf(data + 2 * i, "%2x", &value) != 1)
1617: fatal("x11_request_forwarding: bad authentication data: %.100s", data);
1618: if (i % 4 == 0)
1619: rand = arc4random();
1620: x11_saved_data[i] = value;
1621: x11_fake_data[i] = rand & 0xff;
1622: rand >>= 8;
1623: }
1624: x11_saved_data_len = data_len;
1625: x11_fake_data_len = data_len;
1626:
1627: /* Convert the fake data into hex. */
1628: new_data = xmalloc(2 * data_len + 1);
1629: for (i = 0; i < data_len; i++)
1630: sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]);
1631:
1632: /* Send the request packet. */
1633: packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
1634: packet_put_string(proto, strlen(proto));
1635: packet_put_string(new_data, strlen(new_data));
1636: packet_put_int(screen_number);
1637: packet_send();
1638: packet_write_wait();
1639: xfree(new_data);
1.1 deraadt 1640: }
1641:
1642: /* Sends a message to the server to request authentication fd forwarding. */
1643:
1.25 markus 1644: void
1645: auth_request_forwarding()
1.1 deraadt 1646: {
1.25 markus 1647: packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
1648: packet_send();
1649: packet_write_wait();
1.1 deraadt 1650: }
1651:
1.27 markus 1652: /*
1653: * Returns the name of the forwarded authentication socket. Returns NULL if
1654: * there is no forwarded authentication socket. The returned value points to
1655: * a static buffer.
1656: */
1.1 deraadt 1657:
1.25 markus 1658: char *
1659: auth_get_socket_name()
1.1 deraadt 1660: {
1.25 markus 1661: return channel_forwarded_auth_socket_name;
1.1 deraadt 1662: }
1663:
1.12 markus 1664: /* removes the agent forwarding socket */
1665:
1.25 markus 1666: void
1667: cleanup_socket(void)
1668: {
1669: remove(channel_forwarded_auth_socket_name);
1670: rmdir(channel_forwarded_auth_socket_dir);
1.12 markus 1671: }
1672:
1.27 markus 1673: /*
1674: * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
1675: * This starts forwarding authentication requests.
1676: */
1.1 deraadt 1677:
1.25 markus 1678: void
1679: auth_input_request_forwarding(struct passwd * pw)
1.1 deraadt 1680: {
1.25 markus 1681: int sock, newch;
1682: struct sockaddr_un sunaddr;
1683:
1684: if (auth_get_socket_name() != NULL)
1685: fatal("Protocol error: authentication forwarding requested twice.");
1686:
1687: /* Temporarily drop privileged uid for mkdir/bind. */
1688: temporarily_use_uid(pw->pw_uid);
1689:
1690: /* Allocate a buffer for the socket name, and format the name. */
1691: channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
1692: channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
1693: strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
1694:
1695: /* Create private directory for socket */
1696: if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL)
1697: packet_disconnect("mkdtemp: %.100s", strerror(errno));
1698: snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
1699: channel_forwarded_auth_socket_dir, (int) getpid());
1700:
1701: if (atexit(cleanup_socket) < 0) {
1702: int saved = errno;
1703: cleanup_socket();
1704: packet_disconnect("socket: %.100s", strerror(saved));
1705: }
1706: /* Create the socket. */
1707: sock = socket(AF_UNIX, SOCK_STREAM, 0);
1708: if (sock < 0)
1709: packet_disconnect("socket: %.100s", strerror(errno));
1710:
1711: /* Bind it to the name. */
1712: memset(&sunaddr, 0, sizeof(sunaddr));
1713: sunaddr.sun_family = AF_UNIX;
1714: strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
1715: sizeof(sunaddr.sun_path));
1716:
1717: if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
1718: packet_disconnect("bind: %.100s", strerror(errno));
1719:
1720: /* Restore the privileged uid. */
1721: restore_uid();
1722:
1723: /* Start listening on the socket. */
1724: if (listen(sock, 5) < 0)
1725: packet_disconnect("listen: %.100s", strerror(errno));
1726:
1727: /* Allocate a channel for the authentication agent socket. */
1728: newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock,
1729: xstrdup("auth socket"));
1.32 deraadt 1730: strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
1731: sizeof(channels[newch].path));
1.1 deraadt 1732: }
1733:
1734: /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
1735:
1.25 markus 1736: void
1.41 ! markus 1737: auth_input_open_request(int type, int plen)
1.1 deraadt 1738: {
1.25 markus 1739: int remch, sock, newch;
1740: char *dummyname;
1.41 ! markus 1741:
! 1742: packet_integrity_check(plen, 4, type);
1.25 markus 1743:
1744: /* Read the remote channel number from the message. */
1745: remch = packet_get_int();
1746:
1.27 markus 1747: /*
1748: * Get a connection to the local authentication agent (this may again
1749: * get forwarded).
1750: */
1.25 markus 1751: sock = ssh_get_authentication_socket();
1752:
1.27 markus 1753: /*
1754: * If we could not connect the agent, send an error message back to
1755: * the server. This should never happen unless the agent dies,
1756: * because authentication forwarding is only enabled if we have an
1757: * agent.
1758: */
1.25 markus 1759: if (sock < 0) {
1760: packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1761: packet_put_int(remch);
1762: packet_send();
1763: return;
1764: }
1765: debug("Forwarding authentication connection.");
1.1 deraadt 1766:
1.27 markus 1767: /*
1768: * Dummy host name. This will be freed when the channel is freed; it
1769: * will still be valid in the packet_put_string below since the
1770: * channel cannot yet be freed at that point.
1771: */
1.25 markus 1772: dummyname = xstrdup("authentication agent connection");
1773:
1774: newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
1775: channels[newch].remote_id = remch;
1776:
1777: /* Send a confirmation to the remote host. */
1778: packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1779: packet_put_int(remch);
1780: packet_put_int(newch);
1781: packet_send();
1.1 deraadt 1782: }
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