2 * Platform-independent bits of X11 forwarding.
14 #define GET_16BIT(endian, cp) \
15 (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp))
17 #define PUT_16BIT(endian, cp, val) \
18 (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))
20 const char *const x11_authnames[] = {
21 "", "MIT-MAGIC-COOKIE-1", "XDM-AUTHORIZATION-1"
26 unsigned char clientid[6];
29 struct X11Connection {
30 const struct plug_function_table *fn;
31 /* the above variable absolutely *must* be the first in this structure */
32 unsigned char firstpkt[12]; /* first X data packet */
34 struct X11Display *disp;
36 unsigned char *auth_data;
37 int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize;
39 int throttled, throttle_override;
40 int no_data_sent_to_x_client;
43 struct ssh_channel *c; /* channel structure held by ssh.c */
47 static int xdmseen_cmp(void *a, void *b)
49 struct XDMSeen *sa = a, *sb = b;
50 return sa->time > sb->time ? 1 :
51 sa->time < sb->time ? -1 :
52 memcmp(sa->clientid, sb->clientid, sizeof(sa->clientid));
55 /* Do-nothing "plug" implementation, used by x11_setup_display() when it
56 * creates a trial connection (and then immediately closes it).
57 * XXX: bit out of place here, could in principle live in a platform-
58 * independent network.c or something */
59 static void dummy_plug_log(Plug p, int type, SockAddr addr, int port,
60 const char *error_msg, int error_code) { }
61 static int dummy_plug_closing
62 (Plug p, const char *error_msg, int error_code, int calling_back)
64 static int dummy_plug_receive(Plug p, int urgent, char *data, int len)
66 static void dummy_plug_sent(Plug p, int bufsize) { }
67 static int dummy_plug_accepting(Plug p, accept_fn_t constructor, accept_ctx_t ctx) { return 1; }
68 static const struct plug_function_table dummy_plug = {
69 dummy_plug_log, dummy_plug_closing, dummy_plug_receive,
70 dummy_plug_sent, dummy_plug_accepting
73 struct X11FakeAuth *x11_invent_fake_auth(tree234 *authtree, int authtype)
75 struct X11FakeAuth *auth = snew(struct X11FakeAuth);
78 if (authtype == X11_MIT) {
79 auth->proto = X11_MIT;
81 /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */
83 auth->data = snewn(auth->datalen, unsigned char);
84 auth->xa1_firstblock = NULL;
87 for (i = 0; i < auth->datalen; i++)
88 auth->data[i] = random_byte();
89 if (add234(authtree, auth) == auth)
95 assert(authtype == X11_XDM);
96 auth->proto = X11_XDM;
98 /* XDM-AUTHORIZATION-1. Cookie size is 16 bytes; byte 8 is zero. */
100 auth->data = snewn(auth->datalen, unsigned char);
101 auth->xa1_firstblock = snewn(8, unsigned char);
102 memset(auth->xa1_firstblock, 0, 8);
105 for (i = 0; i < auth->datalen; i++)
106 auth->data[i] = (i == 8 ? 0 : random_byte());
107 memcpy(auth->xa1_firstblock, auth->data, 8);
108 des_encrypt_xdmauth(auth->data + 9, auth->xa1_firstblock, 8);
109 if (add234(authtree, auth) == auth)
113 auth->xdmseen = newtree234(xdmseen_cmp);
115 auth->protoname = dupstr(x11_authnames[auth->proto]);
116 auth->datastring = snewn(auth->datalen * 2 + 1, char);
117 for (i = 0; i < auth->datalen; i++)
118 sprintf(auth->datastring + i*2, "%02x",
124 void x11_free_fake_auth(struct X11FakeAuth *auth)
127 smemclr(auth->data, auth->datalen);
129 sfree(auth->protoname);
130 sfree(auth->datastring);
131 sfree(auth->xa1_firstblock);
132 if (auth->xdmseen != NULL) {
133 struct XDMSeen *seen;
134 while ((seen = delpos234(auth->xdmseen, 0)) != NULL)
136 freetree234(auth->xdmseen);
141 int x11_authcmp(void *av, void *bv)
143 struct X11FakeAuth *a = (struct X11FakeAuth *)av;
144 struct X11FakeAuth *b = (struct X11FakeAuth *)bv;
146 if (a->proto < b->proto)
148 else if (a->proto > b->proto)
151 if (a->proto == X11_MIT) {
152 if (a->datalen < b->datalen)
154 else if (a->datalen > b->datalen)
157 return memcmp(a->data, b->data, a->datalen);
159 assert(a->proto == X11_XDM);
161 return memcmp(a->xa1_firstblock, b->xa1_firstblock, 8);
165 struct X11Display *x11_setup_display(char *display, Conf *conf)
167 struct X11Display *disp = snew(struct X11Display);
170 if (!display || !*display) {
171 localcopy = platform_get_x_display();
172 if (!localcopy || !*localcopy) {
174 localcopy = dupstr(":0"); /* plausible default for any platform */
177 localcopy = dupstr(display);
180 * Parse the display name.
182 * We expect this to have one of the following forms:
184 * - the standard X format which looks like
185 * [ [ protocol '/' ] host ] ':' displaynumber [ '.' screennumber ]
186 * (X11 also permits a double colon to indicate DECnet, but
187 * that's not our problem, thankfully!)
189 * - only seen in the wild on MacOS (so far): a pathname to a
190 * Unix-domain socket, which will typically and confusingly
191 * end in ":0", and which I'm currently distinguishing from
192 * the standard scheme by noting that it starts with '/'.
194 if (localcopy[0] == '/') {
195 disp->unixsocketpath = localcopy;
196 disp->unixdomain = TRUE;
197 disp->hostname = NULL;
198 disp->displaynum = -1;
202 char *colon, *dot, *slash;
203 char *protocol, *hostname;
205 colon = strrchr(localcopy, ':');
209 return NULL; /* FIXME: report a specific error? */
213 dot = strchr(colon, '.');
217 disp->displaynum = atoi(colon);
219 disp->screennum = atoi(dot);
224 hostname = localcopy;
225 if (colon > localcopy) {
226 slash = strchr(localcopy, '/');
229 protocol = localcopy;
234 disp->hostname = *hostname ? dupstr(hostname) : NULL;
237 disp->unixdomain = (!strcmp(protocol, "local") ||
238 !strcmp(protocol, "unix"));
239 else if (!*hostname || !strcmp(hostname, "unix"))
240 disp->unixdomain = platform_uses_x11_unix_by_default;
242 disp->unixdomain = FALSE;
244 if (!disp->hostname && !disp->unixdomain)
245 disp->hostname = dupstr("localhost");
247 disp->unixsocketpath = NULL;
254 * Look up the display hostname, if we need to.
256 if (!disp->unixdomain) {
259 disp->port = 6000 + disp->displaynum;
260 disp->addr = name_lookup(disp->hostname, disp->port,
261 &disp->realhost, conf, ADDRTYPE_UNSPEC);
263 if ((err = sk_addr_error(disp->addr)) != NULL) {
264 sk_addr_free(disp->addr);
265 sfree(disp->hostname);
266 sfree(disp->unixsocketpath);
268 return NULL; /* FIXME: report an error */
273 * Try upgrading an IP-style localhost display to a Unix-socket
274 * display (as the standard X connection libraries do).
276 if (!disp->unixdomain && sk_address_is_local(disp->addr)) {
277 SockAddr ux = platform_get_x11_unix_address(NULL, disp->displaynum);
278 const char *err = sk_addr_error(ux);
280 /* Create trial connection to see if there is a useful Unix-domain
282 const struct plug_function_table *dummy = &dummy_plug;
283 Socket s = sk_new(sk_addr_dup(ux), 0, 0, 0, 0, 0, (Plug)&dummy);
284 err = sk_socket_error(s);
290 sk_addr_free(disp->addr);
291 disp->unixdomain = TRUE;
293 /* Fill in the rest in a moment */
297 if (disp->unixdomain) {
299 disp->addr = platform_get_x11_unix_address(disp->unixsocketpath,
301 if (disp->unixsocketpath)
302 disp->realhost = dupstr(disp->unixsocketpath);
304 disp->realhost = dupprintf("unix:%d", disp->displaynum);
309 * Fetch the local authorisation details.
311 disp->localauthproto = X11_NO_AUTH;
312 disp->localauthdata = NULL;
313 disp->localauthdatalen = 0;
314 platform_get_x11_auth(disp, conf);
319 void x11_free_display(struct X11Display *disp)
321 sfree(disp->hostname);
322 sfree(disp->unixsocketpath);
323 if (disp->localauthdata)
324 smemclr(disp->localauthdata, disp->localauthdatalen);
325 sfree(disp->localauthdata);
326 sk_addr_free(disp->addr);
330 #define XDM_MAXSKEW 20*60 /* 20 minute clock skew should be OK */
332 static char *x11_verify(unsigned long peer_ip, int peer_port,
333 tree234 *authtree, char *proto,
334 unsigned char *data, int dlen,
335 struct X11FakeAuth **auth_ret)
337 struct X11FakeAuth match_dummy; /* for passing to find234 */
338 struct X11FakeAuth *auth;
341 * First, do a lookup in our tree to find the only authorisation
342 * record that _might_ match.
344 if (!strcmp(proto, x11_authnames[X11_MIT])) {
345 match_dummy.proto = X11_MIT;
346 match_dummy.datalen = dlen;
347 match_dummy.data = data;
348 } else if (!strcmp(proto, x11_authnames[X11_XDM])) {
349 match_dummy.proto = X11_XDM;
350 match_dummy.xa1_firstblock = data;
352 return "Unsupported authorisation protocol";
355 if ((auth = find234(authtree, &match_dummy, 0)) == NULL)
356 return "Authorisation not recognised";
359 * If we're using MIT-MAGIC-COOKIE-1, that was all we needed. If
360 * we're doing XDM-AUTHORIZATION-1, though, we have to check the
361 * rest of the auth data.
363 if (auth->proto == X11_XDM) {
367 struct XDMSeen *seen, *ret;
370 return "XDM-AUTHORIZATION-1 data was wrong length";
372 return "cannot do XDM-AUTHORIZATION-1 without remote address data";
373 des_decrypt_xdmauth(auth->data+9, data, 24);
374 if (memcmp(auth->data, data, 8) != 0)
375 return "XDM-AUTHORIZATION-1 data failed check"; /* cookie wrong */
376 if (GET_32BIT_MSB_FIRST(data+8) != peer_ip)
377 return "XDM-AUTHORIZATION-1 data failed check"; /* IP wrong */
378 if ((int)GET_16BIT_MSB_FIRST(data+12) != peer_port)
379 return "XDM-AUTHORIZATION-1 data failed check"; /* port wrong */
380 t = GET_32BIT_MSB_FIRST(data+14);
381 for (i = 18; i < 24; i++)
382 if (data[i] != 0) /* zero padding wrong */
383 return "XDM-AUTHORIZATION-1 data failed check";
385 if (abs(t - tim) > XDM_MAXSKEW)
386 return "XDM-AUTHORIZATION-1 time stamp was too far out";
387 seen = snew(struct XDMSeen);
389 memcpy(seen->clientid, data+8, 6);
390 assert(auth->xdmseen != NULL);
391 ret = add234(auth->xdmseen, seen);
394 return "XDM-AUTHORIZATION-1 data replayed";
396 /* While we're here, purge entries too old to be replayed. */
398 seen = index234(auth->xdmseen, 0);
399 assert(seen != NULL);
400 if (t - seen->time <= XDM_MAXSKEW)
402 sfree(delpos234(auth->xdmseen, 0));
405 /* implement other protocols here if ever required */
411 void x11_get_auth_from_authfile(struct X11Display *disp,
412 const char *authfilename)
415 char *buf, *ptr, *str[4];
417 int family, protocol;
418 int ideal_match = FALSE;
422 * Normally we should look for precisely the details specified in
423 * `disp'. However, there's an oddity when the display is local:
424 * displays like "localhost:0" usually have their details stored
425 * in a Unix-domain-socket record (even if there isn't actually a
426 * real Unix-domain socket available, as with OpenSSH's proxy X11
429 * This is apparently a fudge to get round the meaninglessness of
430 * "localhost" in a shared-home-directory context -- xauth entries
431 * for Unix-domain sockets already disambiguate this by storing
432 * the *local* hostname in the conveniently-blank hostname field,
433 * but IP "localhost" records couldn't do this. So, typically, an
434 * IP "localhost" entry in the auth database isn't present and if
435 * it were it would be ignored.
437 * However, we don't entirely trust that (say) Windows X servers
438 * won't rely on a straight "localhost" entry, bad idea though
439 * that is; so if we can't find a Unix-domain-socket entry we'll
440 * fall back to an IP-based entry if we can find one.
442 int localhost = !disp->unixdomain && sk_address_is_local(disp->addr);
444 authfp = fopen(authfilename, "rb");
448 ourhostname = get_hostname();
450 /* Records in .Xauthority contain four strings of up to 64K each */
451 buf = snewn(65537 * 4, char);
453 while (!ideal_match) {
454 int c, i, j, match = FALSE;
456 #define GET do { c = fgetc(authfp); if (c == EOF) goto done; c = (unsigned char)c; } while (0)
457 /* Expect a big-endian 2-byte number giving address family */
459 GET; family = (family << 8) | c;
460 /* Then expect four strings, each composed of a big-endian 2-byte
461 * length field followed by that many bytes of data */
463 for (i = 0; i < 4; i++) {
465 GET; len[i] = (len[i] << 8) | c;
467 for (j = 0; j < len[i]; j++) {
475 * Now we have a full X authority record in memory. See
476 * whether it matches the display we're trying to
479 * The details we've just read should be interpreted as
482 * - 'family' is the network address family used to
483 * connect to the display. 0 means IPv4; 6 means IPv6;
484 * 256 means Unix-domain sockets.
486 * - str[0] is the network address itself. For IPv4 and
487 * IPv6, this is a string of binary data of the
488 * appropriate length (respectively 4 and 16 bytes)
489 * representing the address in big-endian format, e.g.
490 * 7F 00 00 01 means IPv4 localhost. For Unix-domain
491 * sockets, this is the host name of the machine on
492 * which the Unix-domain display resides (so that an
493 * .Xauthority file on a shared file system can contain
494 * authority entries for Unix-domain displays on
495 * several machines without them clashing).
497 * - str[1] is the display number. I've no idea why
498 * .Xauthority stores this as a string when it has a
499 * perfectly good integer format, but there we go.
501 * - str[2] is the authorisation method, encoded as its
502 * canonical string name (i.e. "MIT-MAGIC-COOKIE-1",
503 * "XDM-AUTHORIZATION-1" or something we don't
506 * - str[3] is the actual authorisation data, stored in
510 if (disp->displaynum < 0 || disp->displaynum != atoi(str[1]))
511 continue; /* not the one */
513 for (protocol = 1; protocol < lenof(x11_authnames); protocol++)
514 if (!strcmp(str[2], x11_authnames[protocol]))
516 if (protocol == lenof(x11_authnames))
517 continue; /* don't recognise this protocol, look for another */
521 if (!disp->unixdomain &&
522 sk_addrtype(disp->addr) == ADDRTYPE_IPV4) {
524 sk_addrcopy(disp->addr, buf);
525 if (len[0] == 4 && !memcmp(str[0], buf, 4)) {
527 /* If this is a "localhost" entry, note it down
528 * but carry on looking for a Unix-domain entry. */
529 ideal_match = !localhost;
534 if (!disp->unixdomain &&
535 sk_addrtype(disp->addr) == ADDRTYPE_IPV6) {
537 sk_addrcopy(disp->addr, buf);
538 if (len[0] == 16 && !memcmp(str[0], buf, 16)) {
540 ideal_match = !localhost;
544 case 256: /* Unix-domain / localhost */
545 if ((disp->unixdomain || localhost)
546 && ourhostname && !strcmp(ourhostname, str[0]))
547 /* A matching Unix-domain socket is always the best
549 match = ideal_match = TRUE;
554 /* Current best guess -- may be overridden if !ideal_match */
555 disp->localauthproto = protocol;
556 sfree(disp->localauthdata); /* free previous guess, if any */
557 disp->localauthdata = snewn(len[3], unsigned char);
558 memcpy(disp->localauthdata, str[3], len[3]);
559 disp->localauthdatalen = len[3];
565 smemclr(buf, 65537 * 4);
570 static void x11_log(Plug p, int type, SockAddr addr, int port,
571 const char *error_msg, int error_code)
573 /* We have no interface to the logging module here, so we drop these. */
576 static void x11_send_init_error(struct X11Connection *conn,
577 const char *err_message);
579 static int x11_closing(Plug plug, const char *error_msg, int error_code,
582 struct X11Connection *xconn = (struct X11Connection *) plug;
586 * Socket error. If we're still at the connection setup stage,
587 * construct an X11 error packet passing on the problem.
589 if (xconn->no_data_sent_to_x_client) {
590 char *err_message = dupprintf("unable to connect to forwarded "
591 "X server: %s", error_msg);
592 x11_send_init_error(xconn, err_message);
597 * Whether we did that or not, now we slam the connection
600 sshfwd_unclean_close(xconn->c, error_msg);
603 * Ordinary EOF received on socket. Send an EOF on the SSH
607 sshfwd_write_eof(xconn->c);
613 static int x11_receive(Plug plug, int urgent, char *data, int len)
615 struct X11Connection *xconn = (struct X11Connection *) plug;
617 if (sshfwd_write(xconn->c, data, len) > 0) {
618 xconn->throttled = 1;
619 xconn->no_data_sent_to_x_client = FALSE;
620 sk_set_frozen(xconn->s, 1);
626 static void x11_sent(Plug plug, int bufsize)
628 struct X11Connection *xconn = (struct X11Connection *) plug;
630 sshfwd_unthrottle(xconn->c, bufsize);
634 * When setting up X forwarding, we should send the screen number
635 * from the specified local display. This function extracts it from
636 * the display string.
638 int x11_get_screen_number(char *display)
642 n = strcspn(display, ":");
645 n = strcspn(display, ".");
648 return atoi(display + n + 1);
652 * Called to set up the X11Connection structure, though this does not
653 * yet connect to an actual server.
655 struct X11Connection *x11_init(tree234 *authtree, void *c,
656 const char *peeraddr, int peerport)
658 static const struct plug_function_table fn_table = {
666 struct X11Connection *xconn;
671 xconn = snew(struct X11Connection);
672 xconn->fn = &fn_table;
673 xconn->auth_protocol = NULL;
674 xconn->authtree = authtree;
676 xconn->data_read = 0;
677 xconn->throttled = xconn->throttle_override = 0;
678 xconn->no_data_sent_to_x_client = TRUE;
682 * We don't actually open a local socket to the X server just yet,
683 * because we don't know which one it is. Instead, we'll wait
684 * until we see the incoming authentication data, which may tell
685 * us what display to connect to, or whether we have to divert
686 * this X forwarding channel to a connection-sharing downstream
687 * rather than handling it ourself.
693 * Stash the peer address we were given in its original text form.
695 xconn->peer_addr = peeraddr ? dupstr(peeraddr) : NULL;
696 xconn->peer_port = peerport;
701 void x11_close(struct X11Connection *xconn)
706 if (xconn->auth_protocol) {
707 sfree(xconn->auth_protocol);
708 sfree(xconn->auth_data);
714 sfree(xconn->peer_addr);
718 void x11_unthrottle(struct X11Connection *xconn)
723 xconn->throttled = 0;
725 sk_set_frozen(xconn->s, xconn->throttled || xconn->throttle_override);
728 void x11_override_throttle(struct X11Connection *xconn, int enable)
733 xconn->throttle_override = enable;
735 sk_set_frozen(xconn->s, xconn->throttled || xconn->throttle_override);
738 static void x11_send_init_error(struct X11Connection *xconn,
739 const char *err_message)
743 unsigned char *reply;
745 full_message = dupprintf("%s X11 proxy: %s\n", appname, err_message);
747 msglen = strlen(full_message);
748 reply = snewn(8 + msglen+1 + 4, unsigned char); /* include zero */
749 msgsize = (msglen + 3) & ~3;
750 reply[0] = 0; /* failure */
751 reply[1] = msglen; /* length of reason string */
752 memcpy(reply + 2, xconn->firstpkt + 2, 4); /* major/minor proto vsn */
753 PUT_16BIT(xconn->firstpkt[0], reply + 6, msgsize >> 2);/* data len */
754 memset(reply + 8, 0, msgsize);
755 memcpy(reply + 8, full_message, msglen);
756 sshfwd_write(xconn->c, (char *)reply, 8 + msgsize);
757 sshfwd_write_eof(xconn->c);
758 xconn->no_data_sent_to_x_client = FALSE;
763 static int x11_parse_ip(const char *addr_string, unsigned long *ip)
767 * See if we can make sense of this string as an IPv4 address, for
768 * XDM-AUTHORIZATION-1 purposes.
772 4 == sscanf(addr_string, "%d.%d.%d.%d", i+0, i+1, i+2, i+3)) {
773 *ip = (i[0] << 24) | (i[1] << 16) | (i[2] << 8) | i[3];
781 * Called to send data down the raw connection.
783 int x11_send(struct X11Connection *xconn, char *data, int len)
789 * Read the first packet.
791 while (len > 0 && xconn->data_read < 12)
792 xconn->firstpkt[xconn->data_read++] = (unsigned char) (len--, *data++);
793 if (xconn->data_read < 12)
797 * If we have not allocated the auth_protocol and auth_data
798 * strings, do so now.
800 if (!xconn->auth_protocol) {
801 xconn->auth_plen = GET_16BIT(xconn->firstpkt[0], xconn->firstpkt + 6);
802 xconn->auth_dlen = GET_16BIT(xconn->firstpkt[0], xconn->firstpkt + 8);
803 xconn->auth_psize = (xconn->auth_plen + 3) & ~3;
804 xconn->auth_dsize = (xconn->auth_dlen + 3) & ~3;
805 /* Leave room for a terminating zero, to make our lives easier. */
806 xconn->auth_protocol = snewn(xconn->auth_psize + 1, char);
807 xconn->auth_data = snewn(xconn->auth_dsize, unsigned char);
811 * Read the auth_protocol and auth_data strings.
814 xconn->data_read < 12 + xconn->auth_psize)
815 xconn->auth_protocol[xconn->data_read++ - 12] = (len--, *data++);
817 xconn->data_read < 12 + xconn->auth_psize + xconn->auth_dsize)
818 xconn->auth_data[xconn->data_read++ - 12 -
819 xconn->auth_psize] = (unsigned char) (len--, *data++);
820 if (xconn->data_read < 12 + xconn->auth_psize + xconn->auth_dsize)
824 * If we haven't verified the authorisation, do so now.
826 if (!xconn->verified) {
828 struct X11FakeAuth *auth_matched = NULL;
829 unsigned long peer_ip;
831 int protomajor, protominor;
834 unsigned char *socketdata;
836 char new_peer_addr[32];
839 protomajor = GET_16BIT(xconn->firstpkt[0], xconn->firstpkt + 2);
840 protominor = GET_16BIT(xconn->firstpkt[0], xconn->firstpkt + 4);
844 xconn->auth_protocol[xconn->auth_plen] = '\0'; /* ASCIZ */
846 if (x11_parse_ip(xconn->peer_addr, &peer_ip))
847 peer_port = xconn->peer_port;
849 peer_port = -1; /* signal no peer address data available */
851 err = x11_verify(peer_ip, peer_port,
852 xconn->authtree, xconn->auth_protocol,
853 xconn->auth_data, xconn->auth_dlen, &auth_matched);
855 x11_send_init_error(xconn, err);
858 assert(auth_matched);
861 * Now we know we're going to accept the connection, and what
862 * X display to connect to. Actually connect to it.
864 xconn->disp = auth_matched->disp;
865 xconn->s = new_connection(sk_addr_dup(xconn->disp->addr),
866 xconn->disp->realhost, xconn->disp->port,
867 0, 1, 0, 0, (Plug) xconn,
868 sshfwd_get_conf(xconn->c));
869 if ((err = sk_socket_error(xconn->s)) != NULL) {
870 char *err_message = dupprintf("unable to connect to"
871 " forwarded X server: %s", err);
872 x11_send_init_error(xconn, err_message);
878 * Write a new connection header containing our replacement
882 socketdata = sk_getxdmdata(xconn->s, &socketdatalen);
883 if (socketdata && socketdatalen==6) {
884 sprintf(new_peer_addr, "%d.%d.%d.%d", socketdata[0],
885 socketdata[1], socketdata[2], socketdata[3]);
886 new_peer_port = GET_16BIT_MSB_FIRST(socketdata + 4);
888 strcpy(new_peer_addr, "0.0.0.0");
892 greeting = x11_make_greeting(xconn->firstpkt[0],
893 protomajor, protominor,
894 xconn->disp->localauthproto,
895 xconn->disp->localauthdata,
896 xconn->disp->localauthdatalen,
897 new_peer_addr, new_peer_port,
900 sk_write(xconn->s, greeting, greeting_len);
902 smemclr(greeting, greeting_len);
912 * After initialisation, just copy data simply.
915 return sk_write(xconn->s, data, len);
918 void x11_send_eof(struct X11Connection *xconn)
921 sk_write_eof(xconn->s);
924 * If EOF is received from the X client before we've got to
925 * the point of actually connecting to an X server, then we
926 * should send an EOF back to the client so that the
927 * forwarded channel will be terminated.
930 sshfwd_write_eof(xconn->c);
934 * Construct an X11 greeting packet, including making up the right
935 * authorisation data.
937 void *x11_make_greeting(int endian, int protomajor, int protominor,
938 int auth_proto, const void *auth_data, int auth_len,
939 const char *peer_addr, int peer_port,
942 unsigned char *greeting;
943 unsigned char realauthdata[64];
944 const char *authname;
945 const unsigned char *authdata;
946 int authnamelen, authnamelen_pad;
947 int authdatalen, authdatalen_pad;
950 authname = x11_authnames[auth_proto];
951 authnamelen = strlen(authname);
952 authnamelen_pad = (authnamelen + 3) & ~3;
954 if (auth_proto == X11_MIT) {
955 authdata = auth_data;
956 authdatalen = auth_len;
957 } else if (auth_proto == X11_XDM && auth_len == 16) {
959 unsigned long peer_ip = 0;
961 x11_parse_ip(peer_addr, &peer_ip);
963 authdata = realauthdata;
965 memset(realauthdata, 0, authdatalen);
966 memcpy(realauthdata, auth_data, 8);
967 PUT_32BIT_MSB_FIRST(realauthdata+8, peer_ip);
968 PUT_16BIT_MSB_FIRST(realauthdata+12, peer_port);
970 PUT_32BIT_MSB_FIRST(realauthdata+14, t);
972 des_encrypt_xdmauth(auth_data + 9, realauthdata, authdatalen);
974 authdata = realauthdata;
978 authdatalen_pad = (authdatalen + 3) & ~3;
979 greeting_len = 12 + authnamelen_pad + authdatalen_pad;
981 greeting = snewn(greeting_len, unsigned char);
982 memset(greeting, 0, greeting_len);
983 greeting[0] = endian;
984 PUT_16BIT(endian, greeting+2, protomajor);
985 PUT_16BIT(endian, greeting+4, protominor);
986 PUT_16BIT(endian, greeting+6, authnamelen);
987 PUT_16BIT(endian, greeting+8, authdatalen);
988 memcpy(greeting+12, authname, authnamelen);
989 memcpy(greeting+12+authnamelen_pad, authdata, authdatalen);
991 smemclr(realauthdata, sizeof(realauthdata));
993 *outlen = greeting_len;