| blob | 70f426a9f4258847ae365fc86e1769da546380c7 |
1 /*\r
2 * Platform-independent bits of X11 forwarding.\r
3 */\r
4 \r
5 #include <stdio.h>\r
6 #include <stdlib.h>\r
7 #include <assert.h>\r
8 #include <time.h>\r
9 \r
10 #include "putty.h"\r
11 #include "ssh.h"\r
12 #include "tree234.h"\r
13 \r
14 #define GET_16BIT(endian, cp) \\r
15 (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp))\r
16 \r
17 #define PUT_16BIT(endian, cp, val) \\r
18 (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val))\r
19 \r
20 const char *const x11_authnames[] = {\r
21 "", "MIT-MAGIC-COOKIE-1", "XDM-AUTHORIZATION-1"\r
22 };\r
23 \r
24 struct XDMSeen {\r
25 unsigned int time;\r
26 unsigned char clientid[6];\r
27 };\r
28 \r
29 struct X11Private {\r
30 const struct plug_function_table *fn;\r
31 /* the above variable absolutely *must* be the first in this structure */\r
32 unsigned char firstpkt[12]; /* first X data packet */\r
33 struct X11Display *disp;\r
34 char *auth_protocol;\r
35 unsigned char *auth_data;\r
36 int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize;\r
37 int verified;\r
38 int throttled, throttle_override;\r
39 unsigned long peer_ip;\r
40 int peer_port;\r
41 void *c; /* data used by ssh.c */\r
42 Socket s;\r
43 };\r
44 \r
45 static int xdmseen_cmp(void *a, void *b)\r
46 {\r
47 struct XDMSeen *sa = a, *sb = b;\r
48 return sa->time > sb->time ? 1 :\r
49 sa->time < sb->time ? -1 :\r
50 memcmp(sa->clientid, sb->clientid, sizeof(sa->clientid));\r
51 }\r
52 \r
53 /* Do-nothing "plug" implementation, used by x11_setup_display() when it\r
54 * creates a trial connection (and then immediately closes it).\r
55 * XXX: bit out of place here, could in principle live in a platform-\r
56 * independent network.c or something */\r
57 static void dummy_plug_log(Plug p, int type, SockAddr addr, int port,\r
58 const char *error_msg, int error_code) { }\r
59 static int dummy_plug_closing\r
60 (Plug p, const char *error_msg, int error_code, int calling_back)\r
61 { return 1; }\r
62 static int dummy_plug_receive(Plug p, int urgent, char *data, int len)\r
63 { return 1; }\r
64 static void dummy_plug_sent(Plug p, int bufsize) { }\r
65 static int dummy_plug_accepting(Plug p, OSSocket sock) { return 1; }\r
66 static const struct plug_function_table dummy_plug = {\r
67 dummy_plug_log, dummy_plug_closing, dummy_plug_receive,\r
68 dummy_plug_sent, dummy_plug_accepting\r
69 };\r
70 \r
71 struct X11Display *x11_setup_display(char *display, int authtype, Conf *conf)\r
72 {\r
73 struct X11Display *disp = snew(struct X11Display);\r
74 char *localcopy;\r
75 int i;\r
76 \r
77 if (!display || !*display) {\r
78 localcopy = platform_get_x_display();\r
79 if (!localcopy || !*localcopy) {\r
80 sfree(localcopy);\r
81 localcopy = dupstr(":0"); /* plausible default for any platform */\r
82 }\r
83 } else\r
84 localcopy = dupstr(display);\r
85 \r
86 /*\r
87 * Parse the display name.\r
88 *\r
89 * We expect this to have one of the following forms:\r
90 * \r
91 * - the standard X format which looks like\r
92 * [ [ protocol '/' ] host ] ':' displaynumber [ '.' screennumber ]\r
93 * (X11 also permits a double colon to indicate DECnet, but\r
94 * that's not our problem, thankfully!)\r
95 *\r
96 * - only seen in the wild on MacOS (so far): a pathname to a\r
97 * Unix-domain socket, which will typically and confusingly\r
98 * end in ":0", and which I'm currently distinguishing from\r
99 * the standard scheme by noting that it starts with '/'.\r
100 */\r
101 if (localcopy[0] == '/') {\r
102 disp->unixsocketpath = localcopy;\r
103 disp->unixdomain = TRUE;\r
104 disp->hostname = NULL;\r
105 disp->displaynum = -1;\r
106 disp->screennum = 0;\r
107 disp->addr = NULL;\r
108 } else {\r
109 char *colon, *dot, *slash;\r
110 char *protocol, *hostname;\r
111 \r
112 colon = strrchr(localcopy, ':');\r
113 if (!colon) {\r
114 sfree(disp);\r
115 sfree(localcopy);\r
116 return NULL; /* FIXME: report a specific error? */\r
117 }\r
118 \r
119 *colon++ = '\0';\r
120 dot = strchr(colon, '.');\r
121 if (dot)\r
122 *dot++ = '\0';\r
123 \r
124 disp->displaynum = atoi(colon);\r
125 if (dot)\r
126 disp->screennum = atoi(dot);\r
127 else\r
128 disp->screennum = 0;\r
129 \r
130 protocol = NULL;\r
131 hostname = localcopy;\r
132 if (colon > localcopy) {\r
133 slash = strchr(localcopy, '/');\r
134 if (slash) {\r
135 *slash++ = '\0';\r
136 protocol = localcopy;\r
137 hostname = slash;\r
138 }\r
139 }\r
140 \r
141 disp->hostname = *hostname ? dupstr(hostname) : NULL;\r
142 \r
143 if (protocol)\r
144 disp->unixdomain = (!strcmp(protocol, "local") ||\r
145 !strcmp(protocol, "unix"));\r
146 else if (!*hostname || !strcmp(hostname, "unix"))\r
147 disp->unixdomain = platform_uses_x11_unix_by_default;\r
148 else\r
149 disp->unixdomain = FALSE;\r
150 \r
151 if (!disp->hostname && !disp->unixdomain)\r
152 disp->hostname = dupstr("localhost");\r
153 \r
154 disp->unixsocketpath = NULL;\r
155 disp->addr = NULL;\r
156 \r
157 sfree(localcopy);\r
158 }\r
159 \r
160 /*\r
161 * Look up the display hostname, if we need to.\r
162 */\r
163 if (!disp->unixdomain) {\r
164 const char *err;\r
165 \r
166 disp->port = 6000 + disp->displaynum;\r
167 disp->addr = name_lookup(disp->hostname, disp->port,\r
168 &disp->realhost, conf, ADDRTYPE_UNSPEC);\r
169 \r
170 if ((err = sk_addr_error(disp->addr)) != NULL) {\r
171 sk_addr_free(disp->addr);\r
172 sfree(disp->hostname);\r
173 sfree(disp->unixsocketpath);\r
174 sfree(disp);\r
175 return NULL; /* FIXME: report an error */\r
176 }\r
177 }\r
178 \r
179 /*\r
180 * Try upgrading an IP-style localhost display to a Unix-socket\r
181 * display (as the standard X connection libraries do).\r
182 */\r
183 if (!disp->unixdomain && sk_address_is_local(disp->addr)) {\r
184 SockAddr ux = platform_get_x11_unix_address(NULL, disp->displaynum);\r
185 const char *err = sk_addr_error(ux);\r
186 if (!err) {\r
187 /* Create trial connection to see if there is a useful Unix-domain\r
188 * socket */\r
189 const struct plug_function_table *dummy = &dummy_plug;\r
190 Socket s = sk_new(sk_addr_dup(ux), 0, 0, 0, 0, 0, (Plug)&dummy);\r
191 err = sk_socket_error(s);\r
192 sk_close(s);\r
193 }\r
194 if (err) {\r
195 sk_addr_free(ux);\r
196 } else {\r
197 sk_addr_free(disp->addr);\r
198 disp->unixdomain = TRUE;\r
199 disp->addr = ux;\r
200 /* Fill in the rest in a moment */\r
201 }\r
202 }\r
203 \r
204 if (disp->unixdomain) {\r
205 if (!disp->addr)\r
206 disp->addr = platform_get_x11_unix_address(disp->unixsocketpath,\r
207 disp->displaynum);\r
208 if (disp->unixsocketpath)\r
209 disp->realhost = dupstr(disp->unixsocketpath);\r
210 else\r
211 disp->realhost = dupprintf("unix:%d", disp->displaynum);\r
212 disp->port = 0;\r
213 }\r
214 \r
215 /*\r
216 * Invent the remote authorisation details.\r
217 */\r
218 if (authtype == X11_MIT) {\r
219 disp->remoteauthproto = X11_MIT;\r
220 \r
221 /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */\r
222 disp->remoteauthdata = snewn(16, unsigned char);\r
223 for (i = 0; i < 16; i++)\r
224 disp->remoteauthdata[i] = random_byte();\r
225 disp->remoteauthdatalen = 16;\r
226 \r
227 disp->xdmseen = NULL;\r
228 } else {\r
229 assert(authtype == X11_XDM);\r
230 disp->remoteauthproto = X11_XDM;\r
231 \r
232 /* XDM-AUTHORIZATION-1. Cookie size is 16 bytes; byte 8 is zero. */\r
233 disp->remoteauthdata = snewn(16, unsigned char);\r
234 for (i = 0; i < 16; i++)\r
235 disp->remoteauthdata[i] = (i == 8 ? 0 : random_byte());\r
236 disp->remoteauthdatalen = 16;\r
237 \r
238 disp->xdmseen = newtree234(xdmseen_cmp);\r
239 }\r
240 disp->remoteauthprotoname = dupstr(x11_authnames[disp->remoteauthproto]);\r
241 disp->remoteauthdatastring = snewn(disp->remoteauthdatalen * 2 + 1, char);\r
242 for (i = 0; i < disp->remoteauthdatalen; i++)\r
243 sprintf(disp->remoteauthdatastring + i*2, "%02x",\r
244 disp->remoteauthdata[i]);\r
245 \r
246 /*\r
247 * Fetch the local authorisation details.\r
248 */\r
249 disp->localauthproto = X11_NO_AUTH;\r
250 disp->localauthdata = NULL;\r
251 disp->localauthdatalen = 0;\r
252 platform_get_x11_auth(disp, conf);\r
253 \r
254 return disp;\r
255 }\r
256 \r
257 void x11_free_display(struct X11Display *disp)\r
258 {\r
259 if (disp->xdmseen != NULL) {\r
260 struct XDMSeen *seen;\r
261 while ((seen = delpos234(disp->xdmseen, 0)) != NULL)\r
262 sfree(seen);\r
263 freetree234(disp->xdmseen);\r
264 }\r
265 sfree(disp->hostname);\r
266 sfree(disp->unixsocketpath);\r
267 if (disp->localauthdata)\r
268 smemclr(disp->localauthdata, disp->localauthdatalen);\r
269 sfree(disp->localauthdata);\r
270 if (disp->remoteauthdata)\r
271 smemclr(disp->remoteauthdata, disp->remoteauthdatalen);\r
272 sfree(disp->remoteauthdata);\r
273 sfree(disp->remoteauthprotoname);\r
274 sfree(disp->remoteauthdatastring);\r
275 sk_addr_free(disp->addr);\r
276 sfree(disp);\r
277 }\r
278 \r
279 #define XDM_MAXSKEW 20*60 /* 20 minute clock skew should be OK */\r
280 \r
281 static char *x11_verify(unsigned long peer_ip, int peer_port,\r
282 struct X11Display *disp, char *proto,\r
283 unsigned char *data, int dlen)\r
284 {\r
285 if (strcmp(proto, x11_authnames[disp->remoteauthproto]) != 0)\r
286 return "wrong authorisation protocol attempted";\r
287 if (disp->remoteauthproto == X11_MIT) {\r
288 if (dlen != disp->remoteauthdatalen)\r
289 return "MIT-MAGIC-COOKIE-1 data was wrong length";\r
290 if (memcmp(disp->remoteauthdata, data, dlen) != 0)\r
291 return "MIT-MAGIC-COOKIE-1 data did not match";\r
292 }\r
293 if (disp->remoteauthproto == X11_XDM) {\r
294 unsigned long t;\r
295 time_t tim;\r
296 int i;\r
297 struct XDMSeen *seen, *ret;\r
298 \r
299 if (dlen != 24)\r
300 return "XDM-AUTHORIZATION-1 data was wrong length";\r
301 if (peer_port == -1)\r
302 return "cannot do XDM-AUTHORIZATION-1 without remote address data";\r
303 des_decrypt_xdmauth(disp->remoteauthdata+9, data, 24);\r
304 if (memcmp(disp->remoteauthdata, data, 8) != 0)\r
305 return "XDM-AUTHORIZATION-1 data failed check"; /* cookie wrong */\r
306 if (GET_32BIT_MSB_FIRST(data+8) != peer_ip)\r
307 return "XDM-AUTHORIZATION-1 data failed check"; /* IP wrong */\r
308 if ((int)GET_16BIT_MSB_FIRST(data+12) != peer_port)\r
309 return "XDM-AUTHORIZATION-1 data failed check"; /* port wrong */\r
310 t = GET_32BIT_MSB_FIRST(data+14);\r
311 for (i = 18; i < 24; i++)\r
312 if (data[i] != 0) /* zero padding wrong */\r
313 return "XDM-AUTHORIZATION-1 data failed check";\r
314 tim = time(NULL);\r
315 if (abs(t - tim) > XDM_MAXSKEW)\r
316 return "XDM-AUTHORIZATION-1 time stamp was too far out";\r
317 seen = snew(struct XDMSeen);\r
318 seen->time = t;\r
319 memcpy(seen->clientid, data+8, 6);\r
320 assert(disp->xdmseen != NULL);\r
321 ret = add234(disp->xdmseen, seen);\r
322 if (ret != seen) {\r
323 sfree(seen);\r
324 return "XDM-AUTHORIZATION-1 data replayed";\r
325 }\r
326 /* While we're here, purge entries too old to be replayed. */\r
327 for (;;) {\r
328 seen = index234(disp->xdmseen, 0);\r
329 assert(seen != NULL);\r
330 if (t - seen->time <= XDM_MAXSKEW)\r
331 break;\r
332 sfree(delpos234(disp->xdmseen, 0));\r
333 }\r
334 }\r
335 /* implement other protocols here if ever required */\r
336 return NULL;\r
337 }\r
338 \r
339 void x11_get_auth_from_authfile(struct X11Display *disp,\r
340 const char *authfilename)\r
341 {\r
342 FILE *authfp;\r
343 char *buf, *ptr, *str[4];\r
344 int len[4];\r
345 int family, protocol;\r
346 int ideal_match = FALSE;\r
347 char *ourhostname;\r
348 \r
349 /*\r
350 * Normally we should look for precisely the details specified in\r
351 * `disp'. However, there's an oddity when the display is local:\r
352 * displays like "localhost:0" usually have their details stored\r
353 * in a Unix-domain-socket record (even if there isn't actually a\r
354 * real Unix-domain socket available, as with OpenSSH's proxy X11\r
355 * server).\r
356 *\r
357 * This is apparently a fudge to get round the meaninglessness of\r
358 * "localhost" in a shared-home-directory context -- xauth entries\r
359 * for Unix-domain sockets already disambiguate this by storing\r
360 * the *local* hostname in the conveniently-blank hostname field,\r
361 * but IP "localhost" records couldn't do this. So, typically, an\r
362 * IP "localhost" entry in the auth database isn't present and if\r
363 * it were it would be ignored.\r
364 *\r
365 * However, we don't entirely trust that (say) Windows X servers\r
366 * won't rely on a straight "localhost" entry, bad idea though\r
367 * that is; so if we can't find a Unix-domain-socket entry we'll\r
368 * fall back to an IP-based entry if we can find one.\r
369 */\r
370 int localhost = !disp->unixdomain && sk_address_is_local(disp->addr);\r
371 \r
372 authfp = fopen(authfilename, "rb");\r
373 if (!authfp)\r
374 return;\r
375 \r
376 ourhostname = get_hostname();\r
377 \r
378 /* Records in .Xauthority contain four strings of up to 64K each */\r
379 buf = snewn(65537 * 4, char);\r
380 \r
381 while (!ideal_match) {\r
382 int c, i, j, match = FALSE;\r
383 \r
384 #define GET do { c = fgetc(authfp); if (c == EOF) goto done; c = (unsigned char)c; } while (0)\r
385 /* Expect a big-endian 2-byte number giving address family */\r
386 GET; family = c;\r
387 GET; family = (family << 8) | c;\r
388 /* Then expect four strings, each composed of a big-endian 2-byte\r
389 * length field followed by that many bytes of data */\r
390 ptr = buf;\r
391 for (i = 0; i < 4; i++) {\r
392 GET; len[i] = c;\r
393 GET; len[i] = (len[i] << 8) | c;\r
394 str[i] = ptr;\r
395 for (j = 0; j < len[i]; j++) {\r
396 GET; *ptr++ = c;\r
397 }\r
398 *ptr++ = '\0';\r
399 }\r
400 #undef GET\r
401 \r
402 /*\r
403 * Now we have a full X authority record in memory. See\r
404 * whether it matches the display we're trying to\r
405 * authenticate to.\r
406 *\r
407 * The details we've just read should be interpreted as\r
408 * follows:\r
409 * \r
410 * - 'family' is the network address family used to\r
411 * connect to the display. 0 means IPv4; 6 means IPv6;\r
412 * 256 means Unix-domain sockets.\r
413 * \r
414 * - str[0] is the network address itself. For IPv4 and\r
415 * IPv6, this is a string of binary data of the\r
416 * appropriate length (respectively 4 and 16 bytes)\r
417 * representing the address in big-endian format, e.g.\r
418 * 7F 00 00 01 means IPv4 localhost. For Unix-domain\r
419 * sockets, this is the host name of the machine on\r
420 * which the Unix-domain display resides (so that an\r
421 * .Xauthority file on a shared file system can contain\r
422 * authority entries for Unix-domain displays on\r
423 * several machines without them clashing).\r
424 * \r
425 * - str[1] is the display number. I've no idea why\r
426 * .Xauthority stores this as a string when it has a\r
427 * perfectly good integer format, but there we go.\r
428 * \r
429 * - str[2] is the authorisation method, encoded as its\r
430 * canonical string name (i.e. "MIT-MAGIC-COOKIE-1",\r
431 * "XDM-AUTHORIZATION-1" or something we don't\r
432 * recognise).\r
433 * \r
434 * - str[3] is the actual authorisation data, stored in\r
435 * binary form.\r
436 */\r
437 \r
438 if (disp->displaynum < 0 || disp->displaynum != atoi(str[1]))\r
439 continue; /* not the one */\r
440 \r
441 for (protocol = 1; protocol < lenof(x11_authnames); protocol++)\r
442 if (!strcmp(str[2], x11_authnames[protocol]))\r
443 break;\r
444 if (protocol == lenof(x11_authnames))\r
445 continue; /* don't recognise this protocol, look for another */\r
446 \r
447 switch (family) {\r
448 case 0: /* IPv4 */\r
449 if (!disp->unixdomain &&\r
450 sk_addrtype(disp->addr) == ADDRTYPE_IPV4) {\r
451 char buf[4];\r
452 sk_addrcopy(disp->addr, buf);\r
453 if (len[0] == 4 && !memcmp(str[0], buf, 4)) {\r
454 match = TRUE;\r
455 /* If this is a "localhost" entry, note it down\r
456 * but carry on looking for a Unix-domain entry. */\r
457 ideal_match = !localhost;\r
458 }\r
459 }\r
460 break;\r
461 case 6: /* IPv6 */\r
462 if (!disp->unixdomain &&\r
463 sk_addrtype(disp->addr) == ADDRTYPE_IPV6) {\r
464 char buf[16];\r
465 sk_addrcopy(disp->addr, buf);\r
466 if (len[0] == 16 && !memcmp(str[0], buf, 16)) {\r
467 match = TRUE;\r
468 ideal_match = !localhost;\r
469 }\r
470 }\r
471 break;\r
472 case 256: /* Unix-domain / localhost */\r
473 if ((disp->unixdomain || localhost)\r
474 && ourhostname && !strcmp(ourhostname, str[0]))\r
475 /* A matching Unix-domain socket is always the best\r
476 * match. */\r
477 match = ideal_match = TRUE;\r
478 break;\r
479 }\r
480 \r
481 if (match) {\r
482 /* Current best guess -- may be overridden if !ideal_match */\r
483 disp->localauthproto = protocol;\r
484 sfree(disp->localauthdata); /* free previous guess, if any */\r
485 disp->localauthdata = snewn(len[3], unsigned char);\r
486 memcpy(disp->localauthdata, str[3], len[3]);\r
487 disp->localauthdatalen = len[3];\r
488 }\r
489 }\r
490 \r
491 done:\r
492 fclose(authfp);\r
493 smemclr(buf, 65537 * 4);\r
494 sfree(buf);\r
495 sfree(ourhostname);\r
496 }\r
497 \r
498 static void x11_log(Plug p, int type, SockAddr addr, int port,\r
499 const char *error_msg, int error_code)\r
500 {\r
501 /* We have no interface to the logging module here, so we drop these. */\r
502 }\r
503 \r
504 static int x11_closing(Plug plug, const char *error_msg, int error_code,\r
505 int calling_back)\r
506 {\r
507 struct X11Private *pr = (struct X11Private *) plug;\r
508 \r
509 if (error_msg) {\r
510 /*\r
511 * Socket error. Slam the connection instantly shut.\r
512 */\r
513 sshfwd_unclean_close(pr->c);\r
514 } else {\r
515 /*\r
516 * Ordinary EOF received on socket. Send an EOF on the SSH\r
517 * channel.\r
518 */\r
519 if (pr->c)\r
520 sshfwd_write_eof(pr->c);\r
521 }\r
522 \r
523 return 1;\r
524 }\r
525 \r
526 static int x11_receive(Plug plug, int urgent, char *data, int len)\r
527 {\r
528 struct X11Private *pr = (struct X11Private *) plug;\r
529 \r
530 if (sshfwd_write(pr->c, data, len) > 0) {\r
531 pr->throttled = 1;\r
532 sk_set_frozen(pr->s, 1);\r
533 }\r
534 \r
535 return 1;\r
536 }\r
537 \r
538 static void x11_sent(Plug plug, int bufsize)\r
539 {\r
540 struct X11Private *pr = (struct X11Private *) plug;\r
541 \r
542 sshfwd_unthrottle(pr->c, bufsize);\r
543 }\r
544 \r
545 /*\r
546 * When setting up X forwarding, we should send the screen number\r
547 * from the specified local display. This function extracts it from\r
548 * the display string.\r
549 */\r
550 int x11_get_screen_number(char *display)\r
551 {\r
552 int n;\r
553 \r
554 n = strcspn(display, ":");\r
555 if (!display[n])\r
556 return 0;\r
557 n = strcspn(display, ".");\r
558 if (!display[n])\r
559 return 0;\r
560 return atoi(display + n + 1);\r
561 }\r
562 \r
563 /*\r
564 * Called to set up the raw connection.\r
565 * \r
566 * Returns an error message, or NULL on success.\r
567 * also, fills the SocketsStructure\r
568 */\r
569 extern const char *x11_init(Socket *s, struct X11Display *disp, void *c,\r
570 const char *peeraddr, int peerport, Conf *conf)\r
571 {\r
572 static const struct plug_function_table fn_table = {\r
573 x11_log,\r
574 x11_closing,\r
575 x11_receive,\r
576 x11_sent,\r
577 NULL\r
578 };\r
579 \r
580 const char *err;\r
581 struct X11Private *pr;\r
582 \r
583 /*\r
584 * Open socket.\r
585 */\r
586 pr = snew(struct X11Private);\r
587 pr->fn = &fn_table;\r
588 pr->auth_protocol = NULL;\r
589 pr->disp = disp;\r
590 pr->verified = 0;\r
591 pr->data_read = 0;\r
592 pr->throttled = pr->throttle_override = 0;\r
593 pr->c = c;\r
594 \r
595 pr->s = *s = new_connection(sk_addr_dup(disp->addr),\r
596 disp->realhost, disp->port,\r
597 0, 1, 0, 0, (Plug) pr, conf);\r
598 if ((err = sk_socket_error(*s)) != NULL) {\r
599 sfree(pr);\r
600 return err;\r
601 }\r
602 \r
603 /*\r
604 * See if we can make sense of the peer address we were given.\r
605 */\r
606 {\r
607 int i[4];\r
608 if (peeraddr &&\r
609 4 == sscanf(peeraddr, "%d.%d.%d.%d", i+0, i+1, i+2, i+3)) {\r
610 pr->peer_ip = (i[0] << 24) | (i[1] << 16) | (i[2] << 8) | i[3];\r
611 pr->peer_port = peerport;\r
612 } else {\r
613 pr->peer_ip = 0;\r
614 pr->peer_port = -1;\r
615 }\r
616 }\r
617 \r
618 sk_set_private_ptr(*s, pr);\r
619 return NULL;\r
620 }\r
621 \r
622 void x11_close(Socket s)\r
623 {\r
624 struct X11Private *pr;\r
625 if (!s)\r
626 return;\r
627 pr = (struct X11Private *) sk_get_private_ptr(s);\r
628 if (pr->auth_protocol) {\r
629 sfree(pr->auth_protocol);\r
630 sfree(pr->auth_data);\r
631 }\r
632 \r
633 sfree(pr);\r
634 \r
635 sk_close(s);\r
636 }\r
637 \r
638 void x11_unthrottle(Socket s)\r
639 {\r
640 struct X11Private *pr;\r
641 if (!s)\r
642 return;\r
643 pr = (struct X11Private *) sk_get_private_ptr(s);\r
644 \r
645 pr->throttled = 0;\r
646 sk_set_frozen(s, pr->throttled || pr->throttle_override);\r
647 }\r
648 \r
649 void x11_override_throttle(Socket s, int enable)\r
650 {\r
651 struct X11Private *pr;\r
652 if (!s)\r
653 return;\r
654 pr = (struct X11Private *) sk_get_private_ptr(s);\r
655 \r
656 pr->throttle_override = enable;\r
657 sk_set_frozen(s, pr->throttled || pr->throttle_override);\r
658 }\r
659 \r
660 /*\r
661 * Called to send data down the raw connection.\r
662 */\r
663 int x11_send(Socket s, char *data, int len)\r
664 {\r
665 struct X11Private *pr;\r
666 if (!s)\r
667 return 0;\r
668 pr = (struct X11Private *) sk_get_private_ptr(s);\r
669 \r
670 /*\r
671 * Read the first packet.\r
672 */\r
673 while (len > 0 && pr->data_read < 12)\r
674 pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++);\r
675 if (pr->data_read < 12)\r
676 return 0;\r
677 \r
678 /*\r
679 * If we have not allocated the auth_protocol and auth_data\r
680 * strings, do so now.\r
681 */\r
682 if (!pr->auth_protocol) {\r
683 pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6);\r
684 pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8);\r
685 pr->auth_psize = (pr->auth_plen + 3) & ~3;\r
686 pr->auth_dsize = (pr->auth_dlen + 3) & ~3;\r
687 /* Leave room for a terminating zero, to make our lives easier. */\r
688 pr->auth_protocol = snewn(pr->auth_psize + 1, char);\r
689 pr->auth_data = snewn(pr->auth_dsize, unsigned char);\r
690 }\r
691 \r
692 /*\r
693 * Read the auth_protocol and auth_data strings.\r
694 */\r
695 while (len > 0 && pr->data_read < 12 + pr->auth_psize)\r
696 pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++);\r
697 while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)\r
698 pr->auth_data[pr->data_read++ - 12 -\r
699 pr->auth_psize] = (unsigned char) (len--, *data++);\r
700 if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)\r
701 return 0;\r
702 \r
703 /*\r
704 * If we haven't verified the authorisation, do so now.\r
705 */\r
706 if (!pr->verified) {\r
707 char *err;\r
708 \r
709 pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */\r
710 err = x11_verify(pr->peer_ip, pr->peer_port,\r
711 pr->disp, pr->auth_protocol,\r
712 pr->auth_data, pr->auth_dlen);\r
713 \r
714 /*\r
715 * If authorisation failed, construct and send an error\r
716 * packet, then terminate the connection.\r
717 */\r
718 if (err) {\r
719 char *message;\r
720 int msglen, msgsize;\r
721 unsigned char *reply;\r
722 \r
723 message = dupprintf("%s X11 proxy: %s", appname, err);\r
724 msglen = strlen(message);\r
725 reply = snewn(8 + msglen+1 + 4, unsigned char); /* include zero */\r
726 msgsize = (msglen + 3) & ~3;\r
727 reply[0] = 0; /* failure */\r
728 reply[1] = msglen; /* length of reason string */\r
729 memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */\r
730 PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */\r
731 memset(reply + 8, 0, msgsize);\r
732 memcpy(reply + 8, message, msglen);\r
733 sshfwd_write(pr->c, (char *)reply, 8 + msgsize);\r
734 sshfwd_write_eof(pr->c);\r
735 sfree(reply);\r
736 sfree(message);\r
737 return 0;\r
738 }\r
739 \r
740 /*\r
741 * Now we know we're going to accept the connection. Strip\r
742 * the fake auth data, and optionally put real auth data in\r
743 * instead.\r
744 */\r
745 {\r
746 char realauthdata[64];\r
747 int realauthlen = 0;\r
748 int authstrlen = strlen(x11_authnames[pr->disp->localauthproto]);\r
749 int buflen = 0; /* initialise to placate optimiser */\r
750 static const char zeroes[4] = { 0,0,0,0 };\r
751 void *buf;\r
752 \r
753 if (pr->disp->localauthproto == X11_MIT) {\r
754 assert(pr->disp->localauthdatalen <= lenof(realauthdata));\r
755 realauthlen = pr->disp->localauthdatalen;\r
756 memcpy(realauthdata, pr->disp->localauthdata, realauthlen);\r
757 } else if (pr->disp->localauthproto == X11_XDM &&\r
758 pr->disp->localauthdatalen == 16 &&\r
759 ((buf = sk_getxdmdata(s, &buflen))!=0)) {\r
760 time_t t;\r
761 realauthlen = (buflen+12+7) & ~7;\r
762 assert(realauthlen <= lenof(realauthdata));\r
763 memset(realauthdata, 0, realauthlen);\r
764 memcpy(realauthdata, pr->disp->localauthdata, 8);\r
765 memcpy(realauthdata+8, buf, buflen);\r
766 t = time(NULL);\r
767 PUT_32BIT_MSB_FIRST(realauthdata+8+buflen, t);\r
768 des_encrypt_xdmauth(pr->disp->localauthdata+9,\r
769 (unsigned char *)realauthdata,\r
770 realauthlen);\r
771 sfree(buf);\r
772 }\r
773 /* implement other auth methods here if required */\r
774 \r
775 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, authstrlen);\r
776 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, realauthlen);\r
777 \r
778 sk_write(s, (char *)pr->firstpkt, 12);\r
779 \r
780 if (authstrlen) {\r
781 sk_write(s, x11_authnames[pr->disp->localauthproto],\r
782 authstrlen);\r
783 sk_write(s, zeroes, 3 & (-authstrlen));\r
784 }\r
785 if (realauthlen) {\r
786 sk_write(s, realauthdata, realauthlen);\r
787 sk_write(s, zeroes, 3 & (-realauthlen));\r
788 }\r
789 }\r
790 pr->verified = 1;\r
791 }\r
792 \r
793 /*\r
794 * After initialisation, just copy data simply.\r
795 */\r
796 \r
797 return sk_write(s, data, len);\r
798 }\r
799 \r
800 void x11_send_eof(Socket s)\r
801 {\r
802 sk_write_eof(s);\r
803 }\r