| blob | 9f22a2364d4e2392d29752903e27fe94b8561be4 |
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,\r
72 const Config *cfg)\r
73 {\r
74 struct X11Display *disp = snew(struct X11Display);\r
75 char *localcopy;\r
76 int i;\r
77 \r
78 if (!display || !*display) {\r
79 localcopy = platform_get_x_display();\r
80 if (!localcopy || !*localcopy) {\r
81 sfree(localcopy);\r
82 localcopy = dupstr(":0"); /* plausible default for any platform */\r
83 }\r
84 } else\r
85 localcopy = dupstr(display);\r
86 \r
87 /*\r
88 * Parse the display name.\r
89 *\r
90 * We expect this to have one of the following forms:\r
91 * \r
92 * - the standard X format which looks like\r
93 * [ [ protocol '/' ] host ] ':' displaynumber [ '.' screennumber ]\r
94 * (X11 also permits a double colon to indicate DECnet, but\r
95 * that's not our problem, thankfully!)\r
96 *\r
97 * - only seen in the wild on MacOS (so far): a pathname to a\r
98 * Unix-domain socket, which will typically and confusingly\r
99 * end in ":0", and which I'm currently distinguishing from\r
100 * the standard scheme by noting that it starts with '/'.\r
101 */\r
102 if (localcopy[0] == '/') {\r
103 disp->unixsocketpath = localcopy;\r
104 disp->unixdomain = TRUE;\r
105 disp->hostname = NULL;\r
106 disp->displaynum = -1;\r
107 disp->screennum = 0;\r
108 disp->addr = NULL;\r
109 } else {\r
110 char *colon, *dot, *slash;\r
111 char *protocol, *hostname;\r
112 \r
113 colon = strrchr(localcopy, ':');\r
114 if (!colon) {\r
115 sfree(disp);\r
116 sfree(localcopy);\r
117 return NULL; /* FIXME: report a specific error? */\r
118 }\r
119 \r
120 *colon++ = '\0';\r
121 dot = strchr(colon, '.');\r
122 if (dot)\r
123 *dot++ = '\0';\r
124 \r
125 disp->displaynum = atoi(colon);\r
126 if (dot)\r
127 disp->screennum = atoi(dot);\r
128 else\r
129 disp->screennum = 0;\r
130 \r
131 protocol = NULL;\r
132 hostname = localcopy;\r
133 if (colon > localcopy) {\r
134 slash = strchr(localcopy, '/');\r
135 if (slash) {\r
136 *slash++ = '\0';\r
137 protocol = localcopy;\r
138 hostname = slash;\r
139 }\r
140 }\r
141 \r
142 disp->hostname = *hostname ? dupstr(hostname) : NULL;\r
143 \r
144 if (protocol)\r
145 disp->unixdomain = (!strcmp(protocol, "local") ||\r
146 !strcmp(protocol, "unix"));\r
147 else if (!*hostname || !strcmp(hostname, "unix"))\r
148 disp->unixdomain = platform_uses_x11_unix_by_default;\r
149 else\r
150 disp->unixdomain = FALSE;\r
151 \r
152 if (!disp->hostname && !disp->unixdomain)\r
153 disp->hostname = dupstr("localhost");\r
154 \r
155 disp->unixsocketpath = NULL;\r
156 disp->addr = NULL;\r
157 \r
158 sfree(localcopy);\r
159 }\r
160 \r
161 /*\r
162 * Look up the display hostname, if we need to.\r
163 */\r
164 if (!disp->unixdomain) {\r
165 const char *err;\r
166 \r
167 disp->port = 6000 + disp->displaynum;\r
168 disp->addr = name_lookup(disp->hostname, disp->port,\r
169 &disp->realhost, cfg, ADDRTYPE_UNSPEC);\r
170 \r
171 if ((err = sk_addr_error(disp->addr)) != NULL) {\r
172 sk_addr_free(disp->addr);\r
173 sfree(disp->hostname);\r
174 sfree(disp->unixsocketpath);\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, cfg);\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 memset(disp->localauthdata, 0, disp->localauthdatalen);\r
269 sfree(disp->localauthdata);\r
270 if (disp->remoteauthdata)\r
271 memset(disp->remoteauthdata, 0, 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 = get_hostname();\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 /* Records in .Xauthority contain four strings of up to 64K each */\r
377 buf = snewn(65537 * 4, char);\r
378 \r
379 while (!ideal_match) {\r
380 int c, i, j, match = FALSE;\r
381 \r
382 #define GET do { c = fgetc(authfp); if (c == EOF) goto done; c = (unsigned char)c; } while (0)\r
383 /* Expect a big-endian 2-byte number giving address family */\r
384 GET; family = c;\r
385 GET; family = (family << 8) | c;\r
386 /* Then expect four strings, each composed of a big-endian 2-byte\r
387 * length field followed by that many bytes of data */\r
388 ptr = buf;\r
389 for (i = 0; i < 4; i++) {\r
390 GET; len[i] = c;\r
391 GET; len[i] = (len[i] << 8) | c;\r
392 str[i] = ptr;\r
393 for (j = 0; j < len[i]; j++) {\r
394 GET; *ptr++ = c;\r
395 }\r
396 *ptr++ = '\0';\r
397 }\r
398 #undef GET\r
399 \r
400 /*\r
401 * Now we have a full X authority record in memory. See\r
402 * whether it matches the display we're trying to\r
403 * authenticate to.\r
404 *\r
405 * The details we've just read should be interpreted as\r
406 * follows:\r
407 * \r
408 * - 'family' is the network address family used to\r
409 * connect to the display. 0 means IPv4; 6 means IPv6;\r
410 * 256 means Unix-domain sockets.\r
411 * \r
412 * - str[0] is the network address itself. For IPv4 and\r
413 * IPv6, this is a string of binary data of the\r
414 * appropriate length (respectively 4 and 16 bytes)\r
415 * representing the address in big-endian format, e.g.\r
416 * 7F 00 00 01 means IPv4 localhost. For Unix-domain\r
417 * sockets, this is the host name of the machine on\r
418 * which the Unix-domain display resides (so that an\r
419 * .Xauthority file on a shared file system can contain\r
420 * authority entries for Unix-domain displays on\r
421 * several machines without them clashing).\r
422 * \r
423 * - str[1] is the display number. I've no idea why\r
424 * .Xauthority stores this as a string when it has a\r
425 * perfectly good integer format, but there we go.\r
426 * \r
427 * - str[2] is the authorisation method, encoded as its\r
428 * canonical string name (i.e. "MIT-MAGIC-COOKIE-1",\r
429 * "XDM-AUTHORIZATION-1" or something we don't\r
430 * recognise).\r
431 * \r
432 * - str[3] is the actual authorisation data, stored in\r
433 * binary form.\r
434 */\r
435 \r
436 if (disp->displaynum < 0 || disp->displaynum != atoi(str[1]))\r
437 continue; /* not the one */\r
438 \r
439 for (protocol = 1; protocol < lenof(x11_authnames); protocol++)\r
440 if (!strcmp(str[2], x11_authnames[protocol]))\r
441 break;\r
442 if (protocol == lenof(x11_authnames))\r
443 continue; /* don't recognise this protocol, look for another */\r
444 \r
445 switch (family) {\r
446 case 0: /* IPv4 */\r
447 if (!disp->unixdomain &&\r
448 sk_addrtype(disp->addr) == ADDRTYPE_IPV4) {\r
449 char buf[4];\r
450 sk_addrcopy(disp->addr, buf);\r
451 if (len[0] == 4 && !memcmp(str[0], buf, 4)) {\r
452 match = TRUE;\r
453 /* If this is a "localhost" entry, note it down\r
454 * but carry on looking for a Unix-domain entry. */\r
455 ideal_match = !localhost;\r
456 }\r
457 }\r
458 break;\r
459 case 6: /* IPv6 */\r
460 if (!disp->unixdomain &&\r
461 sk_addrtype(disp->addr) == ADDRTYPE_IPV6) {\r
462 char buf[16];\r
463 sk_addrcopy(disp->addr, buf);\r
464 if (len[0] == 16 && !memcmp(str[0], buf, 16)) {\r
465 match = TRUE;\r
466 ideal_match = !localhost;\r
467 }\r
468 }\r
469 break;\r
470 case 256: /* Unix-domain / localhost */\r
471 if ((disp->unixdomain || localhost)\r
472 && ourhostname && !strcmp(ourhostname, str[0]))\r
473 /* A matching Unix-domain socket is always the best\r
474 * match. */\r
475 match = ideal_match = TRUE;\r
476 break;\r
477 }\r
478 \r
479 if (match) {\r
480 /* Current best guess -- may be overridden if !ideal_match */\r
481 disp->localauthproto = protocol;\r
482 sfree(disp->localauthdata); /* free previous guess, if any */\r
483 disp->localauthdata = snewn(len[3], unsigned char);\r
484 memcpy(disp->localauthdata, str[3], len[3]);\r
485 disp->localauthdatalen = len[3];\r
486 }\r
487 }\r
488 \r
489 done:\r
490 fclose(authfp);\r
491 memset(buf, 0, 65537 * 4);\r
492 sfree(buf);\r
493 sfree(ourhostname);\r
494 }\r
495 \r
496 static void x11_log(Plug p, int type, SockAddr addr, int port,\r
497 const char *error_msg, int error_code)\r
498 {\r
499 /* We have no interface to the logging module here, so we drop these. */\r
500 }\r
501 \r
502 static int x11_closing(Plug plug, const char *error_msg, int error_code,\r
503 int calling_back)\r
504 {\r
505 struct X11Private *pr = (struct X11Private *) plug;\r
506 \r
507 /*\r
508 * We have no way to communicate down the forwarded connection,\r
509 * so if an error occurred on the socket, we just ignore it\r
510 * and treat it like a proper close.\r
511 */\r
512 sshfwd_close(pr->c);\r
513 x11_close(pr->s);\r
514 return 1;\r
515 }\r
516 \r
517 static int x11_receive(Plug plug, int urgent, char *data, int len)\r
518 {\r
519 struct X11Private *pr = (struct X11Private *) plug;\r
520 \r
521 if (sshfwd_write(pr->c, data, len) > 0) {\r
522 pr->throttled = 1;\r
523 sk_set_frozen(pr->s, 1);\r
524 }\r
525 \r
526 return 1;\r
527 }\r
528 \r
529 static void x11_sent(Plug plug, int bufsize)\r
530 {\r
531 struct X11Private *pr = (struct X11Private *) plug;\r
532 \r
533 sshfwd_unthrottle(pr->c, bufsize);\r
534 }\r
535 \r
536 /*\r
537 * When setting up X forwarding, we should send the screen number\r
538 * from the specified local display. This function extracts it from\r
539 * the display string.\r
540 */\r
541 int x11_get_screen_number(char *display)\r
542 {\r
543 int n;\r
544 \r
545 n = strcspn(display, ":");\r
546 if (!display[n])\r
547 return 0;\r
548 n = strcspn(display, ".");\r
549 if (!display[n])\r
550 return 0;\r
551 return atoi(display + n + 1);\r
552 }\r
553 \r
554 /*\r
555 * Called to set up the raw connection.\r
556 * \r
557 * Returns an error message, or NULL on success.\r
558 * also, fills the SocketsStructure\r
559 */\r
560 extern const char *x11_init(Socket *s, struct X11Display *disp, void *c,\r
561 const char *peeraddr, int peerport,\r
562 const Config *cfg)\r
563 {\r
564 static const struct plug_function_table fn_table = {\r
565 x11_log,\r
566 x11_closing,\r
567 x11_receive,\r
568 x11_sent,\r
569 NULL\r
570 };\r
571 \r
572 const char *err;\r
573 struct X11Private *pr;\r
574 \r
575 /*\r
576 * Open socket.\r
577 */\r
578 pr = snew(struct X11Private);\r
579 pr->fn = &fn_table;\r
580 pr->auth_protocol = NULL;\r
581 pr->disp = disp;\r
582 pr->verified = 0;\r
583 pr->data_read = 0;\r
584 pr->throttled = pr->throttle_override = 0;\r
585 pr->c = c;\r
586 \r
587 pr->s = *s = new_connection(sk_addr_dup(disp->addr),\r
588 disp->realhost, disp->port,\r
589 0, 1, 0, 0, (Plug) pr, cfg);\r
590 if ((err = sk_socket_error(*s)) != NULL) {\r
591 sfree(pr);\r
592 return err;\r
593 }\r
594 \r
595 /*\r
596 * See if we can make sense of the peer address we were given.\r
597 */\r
598 {\r
599 int i[4];\r
600 if (peeraddr &&\r
601 4 == sscanf(peeraddr, "%d.%d.%d.%d", i+0, i+1, i+2, i+3)) {\r
602 pr->peer_ip = (i[0] << 24) | (i[1] << 16) | (i[2] << 8) | i[3];\r
603 pr->peer_port = peerport;\r
604 } else {\r
605 pr->peer_ip = 0;\r
606 pr->peer_port = -1;\r
607 }\r
608 }\r
609 \r
610 sk_set_private_ptr(*s, pr);\r
611 return NULL;\r
612 }\r
613 \r
614 void x11_close(Socket s)\r
615 {\r
616 struct X11Private *pr;\r
617 if (!s)\r
618 return;\r
619 pr = (struct X11Private *) sk_get_private_ptr(s);\r
620 if (pr->auth_protocol) {\r
621 sfree(pr->auth_protocol);\r
622 sfree(pr->auth_data);\r
623 }\r
624 \r
625 sfree(pr);\r
626 \r
627 sk_close(s);\r
628 }\r
629 \r
630 void x11_unthrottle(Socket s)\r
631 {\r
632 struct X11Private *pr;\r
633 if (!s)\r
634 return;\r
635 pr = (struct X11Private *) sk_get_private_ptr(s);\r
636 \r
637 pr->throttled = 0;\r
638 sk_set_frozen(s, pr->throttled || pr->throttle_override);\r
639 }\r
640 \r
641 void x11_override_throttle(Socket s, int enable)\r
642 {\r
643 struct X11Private *pr;\r
644 if (!s)\r
645 return;\r
646 pr = (struct X11Private *) sk_get_private_ptr(s);\r
647 \r
648 pr->throttle_override = enable;\r
649 sk_set_frozen(s, pr->throttled || pr->throttle_override);\r
650 }\r
651 \r
652 /*\r
653 * Called to send data down the raw connection.\r
654 */\r
655 int x11_send(Socket s, char *data, int len)\r
656 {\r
657 struct X11Private *pr;\r
658 if (!s)\r
659 return 0;\r
660 pr = (struct X11Private *) sk_get_private_ptr(s);\r
661 \r
662 /*\r
663 * Read the first packet.\r
664 */\r
665 while (len > 0 && pr->data_read < 12)\r
666 pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++);\r
667 if (pr->data_read < 12)\r
668 return 0;\r
669 \r
670 /*\r
671 * If we have not allocated the auth_protocol and auth_data\r
672 * strings, do so now.\r
673 */\r
674 if (!pr->auth_protocol) {\r
675 pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6);\r
676 pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8);\r
677 pr->auth_psize = (pr->auth_plen + 3) & ~3;\r
678 pr->auth_dsize = (pr->auth_dlen + 3) & ~3;\r
679 /* Leave room for a terminating zero, to make our lives easier. */\r
680 pr->auth_protocol = snewn(pr->auth_psize + 1, char);\r
681 pr->auth_data = snewn(pr->auth_dsize, unsigned char);\r
682 }\r
683 \r
684 /*\r
685 * Read the auth_protocol and auth_data strings.\r
686 */\r
687 while (len > 0 && pr->data_read < 12 + pr->auth_psize)\r
688 pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++);\r
689 while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)\r
690 pr->auth_data[pr->data_read++ - 12 -\r
691 pr->auth_psize] = (unsigned char) (len--, *data++);\r
692 if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize)\r
693 return 0;\r
694 \r
695 /*\r
696 * If we haven't verified the authorisation, do so now.\r
697 */\r
698 if (!pr->verified) {\r
699 char *err;\r
700 \r
701 pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */\r
702 err = x11_verify(pr->peer_ip, pr->peer_port,\r
703 pr->disp, pr->auth_protocol,\r
704 pr->auth_data, pr->auth_dlen);\r
705 \r
706 /*\r
707 * If authorisation failed, construct and send an error\r
708 * packet, then terminate the connection.\r
709 */\r
710 if (err) {\r
711 char *message;\r
712 int msglen, msgsize;\r
713 unsigned char *reply;\r
714 \r
715 message = dupprintf("%s X11 proxy: %s", appname, err);\r
716 msglen = strlen(message);\r
717 reply = snewn(8 + msglen+1 + 4, unsigned char); /* include zero */\r
718 msgsize = (msglen + 3) & ~3;\r
719 reply[0] = 0; /* failure */\r
720 reply[1] = msglen; /* length of reason string */\r
721 memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */\r
722 PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */\r
723 memset(reply + 8, 0, msgsize);\r
724 memcpy(reply + 8, message, msglen);\r
725 sshfwd_write(pr->c, (char *)reply, 8 + msgsize);\r
726 sshfwd_close(pr->c);\r
727 x11_close(s);\r
728 sfree(reply);\r
729 sfree(message);\r
730 return 0;\r
731 }\r
732 \r
733 /*\r
734 * Now we know we're going to accept the connection. Strip\r
735 * the fake auth data, and optionally put real auth data in\r
736 * instead.\r
737 */\r
738 {\r
739 char realauthdata[64];\r
740 int realauthlen = 0;\r
741 int authstrlen = strlen(x11_authnames[pr->disp->localauthproto]);\r
742 int buflen = 0; /* initialise to placate optimiser */\r
743 static const char zeroes[4] = { 0,0,0,0 };\r
744 void *buf;\r
745 \r
746 if (pr->disp->localauthproto == X11_MIT) {\r
747 assert(pr->disp->localauthdatalen <= lenof(realauthdata));\r
748 realauthlen = pr->disp->localauthdatalen;\r
749 memcpy(realauthdata, pr->disp->localauthdata, realauthlen);\r
750 } else if (pr->disp->localauthproto == X11_XDM &&\r
751 pr->disp->localauthdatalen == 16 &&\r
752 ((buf = sk_getxdmdata(s, &buflen))!=0)) {\r
753 time_t t;\r
754 realauthlen = (buflen+12+7) & ~7;\r
755 assert(realauthlen <= lenof(realauthdata));\r
756 memset(realauthdata, 0, realauthlen);\r
757 memcpy(realauthdata, pr->disp->localauthdata, 8);\r
758 memcpy(realauthdata+8, buf, buflen);\r
759 t = time(NULL);\r
760 PUT_32BIT_MSB_FIRST(realauthdata+8+buflen, t);\r
761 des_encrypt_xdmauth(pr->disp->localauthdata+9,\r
762 (unsigned char *)realauthdata,\r
763 realauthlen);\r
764 sfree(buf);\r
765 }\r
766 /* implement other auth methods here if required */\r
767 \r
768 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, authstrlen);\r
769 PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, realauthlen);\r
770 \r
771 sk_write(s, (char *)pr->firstpkt, 12);\r
772 \r
773 if (authstrlen) {\r
774 sk_write(s, x11_authnames[pr->disp->localauthproto],\r
775 authstrlen);\r
776 sk_write(s, zeroes, 3 & (-authstrlen));\r
777 }\r
778 if (realauthlen) {\r
779 sk_write(s, realauthdata, realauthlen);\r
780 sk_write(s, zeroes, 3 & (-realauthlen));\r
781 }\r
782 }\r
783 pr->verified = 1;\r
784 }\r
785 \r
786 /*\r
787 * After initialisation, just copy data simply.\r
788 */\r
789 \r
790 return sk_write(s, data, len);\r
791 }\r