46ed7b64 |
1 | /* |
2 | * Platform-independent bits of X11 forwarding. |
3 | */ |
4 | |
9c964e85 |
5 | #include <stdio.h> |
6 | #include <stdlib.h> |
e0e7dff8 |
7 | #include <assert.h> |
2f92b717 |
8 | #include <time.h> |
9c964e85 |
9 | |
10 | #include "putty.h" |
11 | #include "ssh.h" |
5f8ff48c |
12 | #include "tree234.h" |
9c964e85 |
13 | |
9c964e85 |
14 | #define GET_16BIT(endian, cp) \ |
15 | (endian=='B' ? GET_16BIT_MSB_FIRST(cp) : GET_16BIT_LSB_FIRST(cp)) |
16 | |
17 | #define PUT_16BIT(endian, cp, val) \ |
18 | (endian=='B' ? PUT_16BIT_MSB_FIRST(cp, val) : PUT_16BIT_LSB_FIRST(cp, val)) |
19 | |
e0e7dff8 |
20 | const char *const x11_authnames[] = { |
2f92b717 |
21 | "", "MIT-MAGIC-COOKIE-1", "XDM-AUTHORIZATION-1" |
e0e7dff8 |
22 | }; |
23 | |
5f8ff48c |
24 | struct XDMSeen { |
25 | unsigned int time; |
26 | unsigned char clientid[6]; |
27 | }; |
28 | |
9c964e85 |
29 | struct X11Private { |
302121de |
30 | const struct plug_function_table *fn; |
7e78000d |
31 | /* the above variable absolutely *must* be the first in this structure */ |
32874aea |
32 | unsigned char firstpkt[12]; /* first X data packet */ |
8def70c3 |
33 | struct X11Display *disp; |
9c964e85 |
34 | char *auth_protocol; |
35 | unsigned char *auth_data; |
36 | int data_read, auth_plen, auth_psize, auth_dlen, auth_dsize; |
37 | int verified; |
5471d09a |
38 | int throttled, throttle_override; |
b3ebaa28 |
39 | unsigned long peer_ip; |
40 | int peer_port; |
32874aea |
41 | void *c; /* data used by ssh.c */ |
7e78000d |
42 | Socket s; |
9c964e85 |
43 | }; |
44 | |
5f8ff48c |
45 | static int xdmseen_cmp(void *a, void *b) |
46 | { |
47 | struct XDMSeen *sa = a, *sb = b; |
48 | return sa->time > sb->time ? 1 : |
49 | sa->time < sb->time ? -1 : |
50 | memcmp(sa->clientid, sb->clientid, sizeof(sa->clientid)); |
51 | } |
52 | |
42547ed9 |
53 | /* Do-nothing "plug" implementation, used by x11_setup_display() when it |
54 | * creates a trial connection (and then immediately closes it). |
55 | * XXX: bit out of place here, could in principle live in a platform- |
56 | * independent network.c or something */ |
57 | static void dummy_plug_log(Plug p, int type, SockAddr addr, int port, |
58 | const char *error_msg, int error_code) { } |
59 | static int dummy_plug_closing |
60 | (Plug p, const char *error_msg, int error_code, int calling_back) |
61 | { return 1; } |
62 | static int dummy_plug_receive(Plug p, int urgent, char *data, int len) |
63 | { return 1; } |
64 | static void dummy_plug_sent(Plug p, int bufsize) { } |
65 | static int dummy_plug_accepting(Plug p, OSSocket sock) { return 1; } |
66 | static const struct plug_function_table dummy_plug = { |
67 | dummy_plug_log, dummy_plug_closing, dummy_plug_receive, |
68 | dummy_plug_sent, dummy_plug_accepting |
69 | }; |
70 | |
4a693cfc |
71 | struct X11Display *x11_setup_display(char *display, int authtype, Conf *conf) |
32874aea |
72 | { |
8def70c3 |
73 | struct X11Display *disp = snew(struct X11Display); |
74 | char *localcopy; |
9c964e85 |
75 | int i; |
76 | |
8def70c3 |
77 | if (!display || !*display) { |
78 | localcopy = platform_get_x_display(); |
79 | if (!localcopy || !*localcopy) { |
80 | sfree(localcopy); |
81 | localcopy = dupstr(":0"); /* plausible default for any platform */ |
82 | } |
83 | } else |
84 | localcopy = dupstr(display); |
85 | |
86 | /* |
87 | * Parse the display name. |
88 | * |
89 | * We expect this to have one of the following forms: |
90 | * |
91 | * - the standard X format which looks like |
92 | * [ [ protocol '/' ] host ] ':' displaynumber [ '.' screennumber ] |
93 | * (X11 also permits a double colon to indicate DECnet, but |
94 | * that's not our problem, thankfully!) |
95 | * |
96 | * - only seen in the wild on MacOS (so far): a pathname to a |
97 | * Unix-domain socket, which will typically and confusingly |
98 | * end in ":0", and which I'm currently distinguishing from |
99 | * the standard scheme by noting that it starts with '/'. |
100 | */ |
101 | if (localcopy[0] == '/') { |
102 | disp->unixsocketpath = localcopy; |
103 | disp->unixdomain = TRUE; |
104 | disp->hostname = NULL; |
105 | disp->displaynum = -1; |
106 | disp->screennum = 0; |
42547ed9 |
107 | disp->addr = NULL; |
8def70c3 |
108 | } else { |
109 | char *colon, *dot, *slash; |
110 | char *protocol, *hostname; |
111 | |
112 | colon = strrchr(localcopy, ':'); |
113 | if (!colon) { |
114 | sfree(disp); |
115 | sfree(localcopy); |
116 | return NULL; /* FIXME: report a specific error? */ |
117 | } |
118 | |
119 | *colon++ = '\0'; |
120 | dot = strchr(colon, '.'); |
121 | if (dot) |
122 | *dot++ = '\0'; |
123 | |
124 | disp->displaynum = atoi(colon); |
125 | if (dot) |
126 | disp->screennum = atoi(dot); |
127 | else |
128 | disp->screennum = 0; |
129 | |
130 | protocol = NULL; |
131 | hostname = localcopy; |
132 | if (colon > localcopy) { |
133 | slash = strchr(localcopy, '/'); |
134 | if (slash) { |
135 | *slash++ = '\0'; |
136 | protocol = localcopy; |
137 | hostname = slash; |
138 | } |
139 | } |
140 | |
141 | disp->hostname = *hostname ? dupstr(hostname) : NULL; |
142 | |
143 | if (protocol) |
144 | disp->unixdomain = (!strcmp(protocol, "local") || |
145 | !strcmp(protocol, "unix")); |
566194cc |
146 | else if (!*hostname || !strcmp(hostname, "unix")) |
8def70c3 |
147 | disp->unixdomain = platform_uses_x11_unix_by_default; |
566194cc |
148 | else |
149 | disp->unixdomain = FALSE; |
8def70c3 |
150 | |
151 | if (!disp->hostname && !disp->unixdomain) |
152 | disp->hostname = dupstr("localhost"); |
153 | |
154 | disp->unixsocketpath = NULL; |
42547ed9 |
155 | disp->addr = NULL; |
8def70c3 |
156 | |
157 | sfree(localcopy); |
158 | } |
159 | |
160 | /* |
161 | * Look up the display hostname, if we need to. |
162 | */ |
42547ed9 |
163 | if (!disp->unixdomain) { |
8def70c3 |
164 | const char *err; |
165 | |
166 | disp->port = 6000 + disp->displaynum; |
167 | disp->addr = name_lookup(disp->hostname, disp->port, |
4a693cfc |
168 | &disp->realhost, conf, ADDRTYPE_UNSPEC); |
8def70c3 |
169 | |
170 | if ((err = sk_addr_error(disp->addr)) != NULL) { |
171 | sk_addr_free(disp->addr); |
172 | sfree(disp->hostname); |
173 | sfree(disp->unixsocketpath); |
038ec85e |
174 | sfree(disp); |
8def70c3 |
175 | return NULL; /* FIXME: report an error */ |
176 | } |
177 | } |
178 | |
179 | /* |
42547ed9 |
180 | * Try upgrading an IP-style localhost display to a Unix-socket |
181 | * display (as the standard X connection libraries do). |
182 | */ |
183 | if (!disp->unixdomain && sk_address_is_local(disp->addr)) { |
184 | SockAddr ux = platform_get_x11_unix_address(NULL, disp->displaynum); |
185 | const char *err = sk_addr_error(ux); |
186 | if (!err) { |
187 | /* Create trial connection to see if there is a useful Unix-domain |
188 | * socket */ |
189 | const struct plug_function_table *dummy = &dummy_plug; |
190 | Socket s = sk_new(sk_addr_dup(ux), 0, 0, 0, 0, 0, (Plug)&dummy); |
191 | err = sk_socket_error(s); |
192 | sk_close(s); |
193 | } |
194 | if (err) { |
195 | sk_addr_free(ux); |
196 | } else { |
197 | sk_addr_free(disp->addr); |
198 | disp->unixdomain = TRUE; |
199 | disp->addr = ux; |
200 | /* Fill in the rest in a moment */ |
201 | } |
202 | } |
203 | |
204 | if (disp->unixdomain) { |
205 | if (!disp->addr) |
206 | disp->addr = platform_get_x11_unix_address(disp->unixsocketpath, |
207 | disp->displaynum); |
208 | if (disp->unixsocketpath) |
209 | disp->realhost = dupstr(disp->unixsocketpath); |
210 | else |
211 | disp->realhost = dupprintf("unix:%d", disp->displaynum); |
212 | disp->port = 0; |
213 | } |
214 | |
215 | /* |
8def70c3 |
216 | * Invent the remote authorisation details. |
217 | */ |
218 | if (authtype == X11_MIT) { |
219 | disp->remoteauthproto = X11_MIT; |
e0e7dff8 |
220 | |
b3ebaa28 |
221 | /* MIT-MAGIC-COOKIE-1. Cookie size is 128 bits (16 bytes). */ |
8def70c3 |
222 | disp->remoteauthdata = snewn(16, unsigned char); |
b3ebaa28 |
223 | for (i = 0; i < 16; i++) |
8def70c3 |
224 | disp->remoteauthdata[i] = random_byte(); |
225 | disp->remoteauthdatalen = 16; |
226 | |
227 | disp->xdmseen = NULL; |
b3ebaa28 |
228 | } else { |
8def70c3 |
229 | assert(authtype == X11_XDM); |
230 | disp->remoteauthproto = X11_XDM; |
b3ebaa28 |
231 | |
232 | /* XDM-AUTHORIZATION-1. Cookie size is 16 bytes; byte 8 is zero. */ |
8def70c3 |
233 | disp->remoteauthdata = snewn(16, unsigned char); |
b3ebaa28 |
234 | for (i = 0; i < 16; i++) |
8def70c3 |
235 | disp->remoteauthdata[i] = (i == 8 ? 0 : random_byte()); |
236 | disp->remoteauthdatalen = 16; |
237 | |
238 | disp->xdmseen = newtree234(xdmseen_cmp); |
b3ebaa28 |
239 | } |
8def70c3 |
240 | disp->remoteauthprotoname = dupstr(x11_authnames[disp->remoteauthproto]); |
241 | disp->remoteauthdatastring = snewn(disp->remoteauthdatalen * 2 + 1, char); |
242 | for (i = 0; i < disp->remoteauthdatalen; i++) |
243 | sprintf(disp->remoteauthdatastring + i*2, "%02x", |
244 | disp->remoteauthdata[i]); |
9c964e85 |
245 | |
8def70c3 |
246 | /* |
247 | * Fetch the local authorisation details. |
248 | */ |
249 | disp->localauthproto = X11_NO_AUTH; |
250 | disp->localauthdata = NULL; |
251 | disp->localauthdatalen = 0; |
4a693cfc |
252 | platform_get_x11_auth(disp, conf); |
302121de |
253 | |
8def70c3 |
254 | return disp; |
9c964e85 |
255 | } |
256 | |
8def70c3 |
257 | void x11_free_display(struct X11Display *disp) |
fabd1805 |
258 | { |
8def70c3 |
259 | if (disp->xdmseen != NULL) { |
260 | struct XDMSeen *seen; |
261 | while ((seen = delpos234(disp->xdmseen, 0)) != NULL) |
5f8ff48c |
262 | sfree(seen); |
8def70c3 |
263 | freetree234(disp->xdmseen); |
5f8ff48c |
264 | } |
8def70c3 |
265 | sfree(disp->hostname); |
266 | sfree(disp->unixsocketpath); |
267 | if (disp->localauthdata) |
dfb88efd |
268 | smemclr(disp->localauthdata, disp->localauthdatalen); |
8def70c3 |
269 | sfree(disp->localauthdata); |
270 | if (disp->remoteauthdata) |
dfb88efd |
271 | smemclr(disp->remoteauthdata, disp->remoteauthdatalen); |
8def70c3 |
272 | sfree(disp->remoteauthdata); |
273 | sfree(disp->remoteauthprotoname); |
274 | sfree(disp->remoteauthdatastring); |
275 | sk_addr_free(disp->addr); |
276 | sfree(disp); |
e0e7dff8 |
277 | } |
278 | |
5f8ff48c |
279 | #define XDM_MAXSKEW 20*60 /* 20 minute clock skew should be OK */ |
280 | |
b3ebaa28 |
281 | static char *x11_verify(unsigned long peer_ip, int peer_port, |
8def70c3 |
282 | struct X11Display *disp, char *proto, |
b3ebaa28 |
283 | unsigned char *data, int dlen) |
32874aea |
284 | { |
8def70c3 |
285 | if (strcmp(proto, x11_authnames[disp->remoteauthproto]) != 0) |
286 | return "wrong authorisation protocol attempted"; |
287 | if (disp->remoteauthproto == X11_MIT) { |
288 | if (dlen != disp->remoteauthdatalen) |
b3ebaa28 |
289 | return "MIT-MAGIC-COOKIE-1 data was wrong length"; |
8def70c3 |
290 | if (memcmp(disp->remoteauthdata, data, dlen) != 0) |
b3ebaa28 |
291 | return "MIT-MAGIC-COOKIE-1 data did not match"; |
292 | } |
8def70c3 |
293 | if (disp->remoteauthproto == X11_XDM) { |
b3ebaa28 |
294 | unsigned long t; |
295 | time_t tim; |
296 | int i; |
5f8ff48c |
297 | struct XDMSeen *seen, *ret; |
b3ebaa28 |
298 | |
299 | if (dlen != 24) |
300 | return "XDM-AUTHORIZATION-1 data was wrong length"; |
301 | if (peer_port == -1) |
302 | return "cannot do XDM-AUTHORIZATION-1 without remote address data"; |
8def70c3 |
303 | des_decrypt_xdmauth(disp->remoteauthdata+9, data, 24); |
304 | if (memcmp(disp->remoteauthdata, data, 8) != 0) |
b3ebaa28 |
305 | return "XDM-AUTHORIZATION-1 data failed check"; /* cookie wrong */ |
306 | if (GET_32BIT_MSB_FIRST(data+8) != peer_ip) |
307 | return "XDM-AUTHORIZATION-1 data failed check"; /* IP wrong */ |
308 | if ((int)GET_16BIT_MSB_FIRST(data+12) != peer_port) |
309 | return "XDM-AUTHORIZATION-1 data failed check"; /* port wrong */ |
310 | t = GET_32BIT_MSB_FIRST(data+14); |
311 | for (i = 18; i < 24; i++) |
312 | if (data[i] != 0) /* zero padding wrong */ |
313 | return "XDM-AUTHORIZATION-1 data failed check"; |
314 | tim = time(NULL); |
5f8ff48c |
315 | if (abs(t - tim) > XDM_MAXSKEW) |
b3ebaa28 |
316 | return "XDM-AUTHORIZATION-1 time stamp was too far out"; |
5f8ff48c |
317 | seen = snew(struct XDMSeen); |
318 | seen->time = t; |
319 | memcpy(seen->clientid, data+8, 6); |
8def70c3 |
320 | assert(disp->xdmseen != NULL); |
321 | ret = add234(disp->xdmseen, seen); |
5f8ff48c |
322 | if (ret != seen) { |
323 | sfree(seen); |
324 | return "XDM-AUTHORIZATION-1 data replayed"; |
325 | } |
326 | /* While we're here, purge entries too old to be replayed. */ |
327 | for (;;) { |
8def70c3 |
328 | seen = index234(disp->xdmseen, 0); |
5f8ff48c |
329 | assert(seen != NULL); |
330 | if (t - seen->time <= XDM_MAXSKEW) |
331 | break; |
8def70c3 |
332 | sfree(delpos234(disp->xdmseen, 0)); |
5f8ff48c |
333 | } |
e0e7dff8 |
334 | } |
335 | /* implement other protocols here if ever required */ |
b3ebaa28 |
336 | return NULL; |
9c964e85 |
337 | } |
338 | |
8def70c3 |
339 | void x11_get_auth_from_authfile(struct X11Display *disp, |
340 | const char *authfilename) |
341 | { |
342 | FILE *authfp; |
343 | char *buf, *ptr, *str[4]; |
344 | int len[4]; |
345 | int family, protocol; |
42547ed9 |
346 | int ideal_match = FALSE; |
038ec85e |
347 | char *ourhostname; |
42547ed9 |
348 | |
349 | /* |
350 | * Normally we should look for precisely the details specified in |
351 | * `disp'. However, there's an oddity when the display is local: |
352 | * displays like "localhost:0" usually have their details stored |
353 | * in a Unix-domain-socket record (even if there isn't actually a |
354 | * real Unix-domain socket available, as with OpenSSH's proxy X11 |
355 | * server). |
356 | * |
357 | * This is apparently a fudge to get round the meaninglessness of |
358 | * "localhost" in a shared-home-directory context -- xauth entries |
359 | * for Unix-domain sockets already disambiguate this by storing |
360 | * the *local* hostname in the conveniently-blank hostname field, |
361 | * but IP "localhost" records couldn't do this. So, typically, an |
362 | * IP "localhost" entry in the auth database isn't present and if |
363 | * it were it would be ignored. |
364 | * |
365 | * However, we don't entirely trust that (say) Windows X servers |
366 | * won't rely on a straight "localhost" entry, bad idea though |
367 | * that is; so if we can't find a Unix-domain-socket entry we'll |
368 | * fall back to an IP-based entry if we can find one. |
369 | */ |
370 | int localhost = !disp->unixdomain && sk_address_is_local(disp->addr); |
8def70c3 |
371 | |
372 | authfp = fopen(authfilename, "rb"); |
373 | if (!authfp) |
374 | return; |
375 | |
038ec85e |
376 | ourhostname = get_hostname(); |
377 | |
8def70c3 |
378 | /* Records in .Xauthority contain four strings of up to 64K each */ |
379 | buf = snewn(65537 * 4, char); |
380 | |
42547ed9 |
381 | while (!ideal_match) { |
382 | int c, i, j, match = FALSE; |
8def70c3 |
383 | |
384 | #define GET do { c = fgetc(authfp); if (c == EOF) goto done; c = (unsigned char)c; } while (0) |
385 | /* Expect a big-endian 2-byte number giving address family */ |
386 | GET; family = c; |
387 | GET; family = (family << 8) | c; |
388 | /* Then expect four strings, each composed of a big-endian 2-byte |
389 | * length field followed by that many bytes of data */ |
390 | ptr = buf; |
391 | for (i = 0; i < 4; i++) { |
392 | GET; len[i] = c; |
393 | GET; len[i] = (len[i] << 8) | c; |
394 | str[i] = ptr; |
395 | for (j = 0; j < len[i]; j++) { |
396 | GET; *ptr++ = c; |
397 | } |
398 | *ptr++ = '\0'; |
399 | } |
400 | #undef GET |
401 | |
402 | /* |
403 | * Now we have a full X authority record in memory. See |
404 | * whether it matches the display we're trying to |
405 | * authenticate to. |
406 | * |
407 | * The details we've just read should be interpreted as |
408 | * follows: |
409 | * |
410 | * - 'family' is the network address family used to |
411 | * connect to the display. 0 means IPv4; 6 means IPv6; |
412 | * 256 means Unix-domain sockets. |
413 | * |
414 | * - str[0] is the network address itself. For IPv4 and |
415 | * IPv6, this is a string of binary data of the |
416 | * appropriate length (respectively 4 and 16 bytes) |
417 | * representing the address in big-endian format, e.g. |
418 | * 7F 00 00 01 means IPv4 localhost. For Unix-domain |
419 | * sockets, this is the host name of the machine on |
420 | * which the Unix-domain display resides (so that an |
421 | * .Xauthority file on a shared file system can contain |
422 | * authority entries for Unix-domain displays on |
423 | * several machines without them clashing). |
424 | * |
425 | * - str[1] is the display number. I've no idea why |
426 | * .Xauthority stores this as a string when it has a |
427 | * perfectly good integer format, but there we go. |
428 | * |
429 | * - str[2] is the authorisation method, encoded as its |
430 | * canonical string name (i.e. "MIT-MAGIC-COOKIE-1", |
431 | * "XDM-AUTHORIZATION-1" or something we don't |
432 | * recognise). |
433 | * |
434 | * - str[3] is the actual authorisation data, stored in |
435 | * binary form. |
436 | */ |
437 | |
438 | if (disp->displaynum < 0 || disp->displaynum != atoi(str[1])) |
439 | continue; /* not the one */ |
440 | |
441 | for (protocol = 1; protocol < lenof(x11_authnames); protocol++) |
442 | if (!strcmp(str[2], x11_authnames[protocol])) |
443 | break; |
444 | if (protocol == lenof(x11_authnames)) |
445 | continue; /* don't recognise this protocol, look for another */ |
446 | |
447 | switch (family) { |
42547ed9 |
448 | case 0: /* IPv4 */ |
8def70c3 |
449 | if (!disp->unixdomain && |
450 | sk_addrtype(disp->addr) == ADDRTYPE_IPV4) { |
451 | char buf[4]; |
452 | sk_addrcopy(disp->addr, buf); |
42547ed9 |
453 | if (len[0] == 4 && !memcmp(str[0], buf, 4)) { |
454 | match = TRUE; |
455 | /* If this is a "localhost" entry, note it down |
456 | * but carry on looking for a Unix-domain entry. */ |
457 | ideal_match = !localhost; |
458 | } |
8def70c3 |
459 | } |
460 | break; |
42547ed9 |
461 | case 6: /* IPv6 */ |
8def70c3 |
462 | if (!disp->unixdomain && |
463 | sk_addrtype(disp->addr) == ADDRTYPE_IPV6) { |
464 | char buf[16]; |
465 | sk_addrcopy(disp->addr, buf); |
42547ed9 |
466 | if (len[0] == 16 && !memcmp(str[0], buf, 16)) { |
467 | match = TRUE; |
468 | ideal_match = !localhost; |
469 | } |
8def70c3 |
470 | } |
471 | break; |
42547ed9 |
472 | case 256: /* Unix-domain / localhost */ |
473 | if ((disp->unixdomain || localhost) |
474 | && ourhostname && !strcmp(ourhostname, str[0])) |
475 | /* A matching Unix-domain socket is always the best |
476 | * match. */ |
477 | match = ideal_match = TRUE; |
8def70c3 |
478 | break; |
479 | } |
8def70c3 |
480 | |
42547ed9 |
481 | if (match) { |
482 | /* Current best guess -- may be overridden if !ideal_match */ |
483 | disp->localauthproto = protocol; |
484 | sfree(disp->localauthdata); /* free previous guess, if any */ |
485 | disp->localauthdata = snewn(len[3], unsigned char); |
486 | memcpy(disp->localauthdata, str[3], len[3]); |
487 | disp->localauthdatalen = len[3]; |
488 | } |
489 | } |
8def70c3 |
490 | |
491 | done: |
492 | fclose(authfp); |
dfb88efd |
493 | smemclr(buf, 65537 * 4); |
8def70c3 |
494 | sfree(buf); |
42547ed9 |
495 | sfree(ourhostname); |
8def70c3 |
496 | } |
497 | |
7555d6a5 |
498 | static void x11_log(Plug p, int type, SockAddr addr, int port, |
499 | const char *error_msg, int error_code) |
500 | { |
501 | /* We have no interface to the logging module here, so we drop these. */ |
502 | } |
503 | |
cbe2d68f |
504 | static int x11_closing(Plug plug, const char *error_msg, int error_code, |
32874aea |
505 | int calling_back) |
506 | { |
7e78000d |
507 | struct X11Private *pr = (struct X11Private *) plug; |
508 | |
167ff003 |
509 | if (error_msg) { |
510 | /* |
511 | * Socket error. Slam the connection instantly shut. |
512 | */ |
513 | sshfwd_unclean_close(pr->c); |
514 | } else { |
515 | /* |
516 | * Ordinary EOF received on socket. Send an EOF on the SSH |
517 | * channel. |
518 | */ |
519 | if (pr->c) |
520 | sshfwd_write_eof(pr->c); |
521 | } |
522 | |
7e78000d |
523 | return 1; |
524 | } |
525 | |
32874aea |
526 | static int x11_receive(Plug plug, int urgent, char *data, int len) |
527 | { |
7e78000d |
528 | struct X11Private *pr = (struct X11Private *) plug; |
9c964e85 |
529 | |
5471d09a |
530 | if (sshfwd_write(pr->c, data, len) > 0) { |
531 | pr->throttled = 1; |
532 | sk_set_frozen(pr->s, 1); |
533 | } |
534 | |
9c964e85 |
535 | return 1; |
536 | } |
537 | |
5471d09a |
538 | static void x11_sent(Plug plug, int bufsize) |
539 | { |
540 | struct X11Private *pr = (struct X11Private *) plug; |
541 | |
542 | sshfwd_unthrottle(pr->c, bufsize); |
543 | } |
544 | |
9c964e85 |
545 | /* |
421d6835 |
546 | * When setting up X forwarding, we should send the screen number |
547 | * from the specified local display. This function extracts it from |
548 | * the display string. |
549 | */ |
550 | int x11_get_screen_number(char *display) |
551 | { |
552 | int n; |
553 | |
554 | n = strcspn(display, ":"); |
555 | if (!display[n]) |
556 | return 0; |
557 | n = strcspn(display, "."); |
558 | if (!display[n]) |
559 | return 0; |
560 | return atoi(display + n + 1); |
561 | } |
562 | |
563 | /* |
9c964e85 |
564 | * Called to set up the raw connection. |
565 | * |
566 | * Returns an error message, or NULL on success. |
567 | * also, fills the SocketsStructure |
9c964e85 |
568 | */ |
8def70c3 |
569 | extern const char *x11_init(Socket *s, struct X11Display *disp, void *c, |
4a693cfc |
570 | const char *peeraddr, int peerport, Conf *conf) |
32874aea |
571 | { |
302121de |
572 | static const struct plug_function_table fn_table = { |
7555d6a5 |
573 | x11_log, |
7e78000d |
574 | x11_closing, |
5471d09a |
575 | x11_receive, |
576 | x11_sent, |
577 | NULL |
7e78000d |
578 | }; |
579 | |
cbe2d68f |
580 | const char *err; |
9c964e85 |
581 | struct X11Private *pr; |
582 | |
9c964e85 |
583 | /* |
584 | * Open socket. |
585 | */ |
3d88e64d |
586 | pr = snew(struct X11Private); |
7e78000d |
587 | pr->fn = &fn_table; |
9c964e85 |
588 | pr->auth_protocol = NULL; |
8def70c3 |
589 | pr->disp = disp; |
9c964e85 |
590 | pr->verified = 0; |
591 | pr->data_read = 0; |
5471d09a |
592 | pr->throttled = pr->throttle_override = 0; |
9c964e85 |
593 | pr->c = c; |
594 | |
8def70c3 |
595 | pr->s = *s = new_connection(sk_addr_dup(disp->addr), |
596 | disp->realhost, disp->port, |
4a693cfc |
597 | 0, 1, 0, 0, (Plug) pr, conf); |
6518ea7b |
598 | if ((err = sk_socket_error(*s)) != NULL) { |
32874aea |
599 | sfree(pr); |
7e78000d |
600 | return err; |
601 | } |
602 | |
b3ebaa28 |
603 | /* |
604 | * See if we can make sense of the peer address we were given. |
605 | */ |
606 | { |
607 | int i[4]; |
608 | if (peeraddr && |
609 | 4 == sscanf(peeraddr, "%d.%d.%d.%d", i+0, i+1, i+2, i+3)) { |
610 | pr->peer_ip = (i[0] << 24) | (i[1] << 16) | (i[2] << 8) | i[3]; |
611 | pr->peer_port = peerport; |
612 | } else { |
613 | pr->peer_ip = 0; |
614 | pr->peer_port = -1; |
615 | } |
616 | } |
617 | |
9c964e85 |
618 | sk_set_private_ptr(*s, pr); |
9c964e85 |
619 | return NULL; |
620 | } |
621 | |
32874aea |
622 | void x11_close(Socket s) |
623 | { |
624 | struct X11Private *pr; |
d74d141c |
625 | if (!s) |
626 | return; |
627 | pr = (struct X11Private *) sk_get_private_ptr(s); |
9c964e85 |
628 | if (pr->auth_protocol) { |
32874aea |
629 | sfree(pr->auth_protocol); |
630 | sfree(pr->auth_data); |
9c964e85 |
631 | } |
632 | |
633 | sfree(pr); |
634 | |
635 | sk_close(s); |
636 | } |
637 | |
5471d09a |
638 | void x11_unthrottle(Socket s) |
639 | { |
640 | struct X11Private *pr; |
641 | if (!s) |
642 | return; |
643 | pr = (struct X11Private *) sk_get_private_ptr(s); |
644 | |
645 | pr->throttled = 0; |
646 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
647 | } |
648 | |
649 | void x11_override_throttle(Socket s, int enable) |
650 | { |
651 | struct X11Private *pr; |
652 | if (!s) |
653 | return; |
654 | pr = (struct X11Private *) sk_get_private_ptr(s); |
655 | |
656 | pr->throttle_override = enable; |
657 | sk_set_frozen(s, pr->throttled || pr->throttle_override); |
658 | } |
659 | |
9c964e85 |
660 | /* |
661 | * Called to send data down the raw connection. |
662 | */ |
5471d09a |
663 | int x11_send(Socket s, char *data, int len) |
32874aea |
664 | { |
970f2b02 |
665 | struct X11Private *pr; |
666 | if (!s) |
5471d09a |
667 | return 0; |
970f2b02 |
668 | pr = (struct X11Private *) sk_get_private_ptr(s); |
9c964e85 |
669 | |
670 | /* |
671 | * Read the first packet. |
672 | */ |
673 | while (len > 0 && pr->data_read < 12) |
32874aea |
674 | pr->firstpkt[pr->data_read++] = (unsigned char) (len--, *data++); |
9c964e85 |
675 | if (pr->data_read < 12) |
5471d09a |
676 | return 0; |
9c964e85 |
677 | |
678 | /* |
679 | * If we have not allocated the auth_protocol and auth_data |
680 | * strings, do so now. |
681 | */ |
682 | if (!pr->auth_protocol) { |
32874aea |
683 | pr->auth_plen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 6); |
684 | pr->auth_dlen = GET_16BIT(pr->firstpkt[0], pr->firstpkt + 8); |
685 | pr->auth_psize = (pr->auth_plen + 3) & ~3; |
686 | pr->auth_dsize = (pr->auth_dlen + 3) & ~3; |
687 | /* Leave room for a terminating zero, to make our lives easier. */ |
3d88e64d |
688 | pr->auth_protocol = snewn(pr->auth_psize + 1, char); |
92d60585 |
689 | pr->auth_data = snewn(pr->auth_dsize, unsigned char); |
9c964e85 |
690 | } |
691 | |
692 | /* |
693 | * Read the auth_protocol and auth_data strings. |
694 | */ |
695 | while (len > 0 && pr->data_read < 12 + pr->auth_psize) |
32874aea |
696 | pr->auth_protocol[pr->data_read++ - 12] = (len--, *data++); |
9c964e85 |
697 | while (len > 0 && pr->data_read < 12 + pr->auth_psize + pr->auth_dsize) |
32874aea |
698 | pr->auth_data[pr->data_read++ - 12 - |
699 | pr->auth_psize] = (unsigned char) (len--, *data++); |
9c964e85 |
700 | if (pr->data_read < 12 + pr->auth_psize + pr->auth_dsize) |
5471d09a |
701 | return 0; |
9c964e85 |
702 | |
703 | /* |
8def70c3 |
704 | * If we haven't verified the authorisation, do so now. |
9c964e85 |
705 | */ |
706 | if (!pr->verified) { |
b3ebaa28 |
707 | char *err; |
32874aea |
708 | |
709 | pr->auth_protocol[pr->auth_plen] = '\0'; /* ASCIZ */ |
b3ebaa28 |
710 | err = x11_verify(pr->peer_ip, pr->peer_port, |
8def70c3 |
711 | pr->disp, pr->auth_protocol, |
302121de |
712 | pr->auth_data, pr->auth_dlen); |
32874aea |
713 | |
714 | /* |
8def70c3 |
715 | * If authorisation failed, construct and send an error |
32874aea |
716 | * packet, then terminate the connection. |
717 | */ |
b3ebaa28 |
718 | if (err) { |
719 | char *message; |
720 | int msglen, msgsize; |
721 | unsigned char *reply; |
722 | |
42704c97 |
723 | message = dupprintf("%s X11 proxy: %s", appname, err); |
b3ebaa28 |
724 | msglen = strlen(message); |
3d88e64d |
725 | reply = snewn(8 + msglen+1 + 4, unsigned char); /* include zero */ |
b3ebaa28 |
726 | msgsize = (msglen + 3) & ~3; |
32874aea |
727 | reply[0] = 0; /* failure */ |
728 | reply[1] = msglen; /* length of reason string */ |
729 | memcpy(reply + 2, pr->firstpkt + 2, 4); /* major/minor proto vsn */ |
75105663 |
730 | PUT_16BIT(pr->firstpkt[0], reply + 6, msgsize >> 2);/* data len */ |
32874aea |
731 | memset(reply + 8, 0, msgsize); |
732 | memcpy(reply + 8, message, msglen); |
f28e6b7c |
733 | sshfwd_write(pr->c, (char *)reply, 8 + msgsize); |
bc06669b |
734 | sshfwd_write_eof(pr->c); |
b3ebaa28 |
735 | sfree(reply); |
736 | sfree(message); |
5471d09a |
737 | return 0; |
32874aea |
738 | } |
739 | |
740 | /* |
741 | * Now we know we're going to accept the connection. Strip |
e0e7dff8 |
742 | * the fake auth data, and optionally put real auth data in |
743 | * instead. |
32874aea |
744 | */ |
e0e7dff8 |
745 | { |
746 | char realauthdata[64]; |
747 | int realauthlen = 0; |
8def70c3 |
748 | int authstrlen = strlen(x11_authnames[pr->disp->localauthproto]); |
62ddb51e |
749 | int buflen = 0; /* initialise to placate optimiser */ |
e0e7dff8 |
750 | static const char zeroes[4] = { 0,0,0,0 }; |
0a4022a1 |
751 | void *buf; |
e0e7dff8 |
752 | |
8def70c3 |
753 | if (pr->disp->localauthproto == X11_MIT) { |
754 | assert(pr->disp->localauthdatalen <= lenof(realauthdata)); |
755 | realauthlen = pr->disp->localauthdatalen; |
756 | memcpy(realauthdata, pr->disp->localauthdata, realauthlen); |
757 | } else if (pr->disp->localauthproto == X11_XDM && |
758 | pr->disp->localauthdatalen == 16 && |
0c5ca1f3 |
759 | ((buf = sk_getxdmdata(s, &buflen))!=0)) { |
2f92b717 |
760 | time_t t; |
0a4022a1 |
761 | realauthlen = (buflen+12+7) & ~7; |
762 | assert(realauthlen <= lenof(realauthdata)); |
763 | memset(realauthdata, 0, realauthlen); |
8def70c3 |
764 | memcpy(realauthdata, pr->disp->localauthdata, 8); |
0a4022a1 |
765 | memcpy(realauthdata+8, buf, buflen); |
2f92b717 |
766 | t = time(NULL); |
0a4022a1 |
767 | PUT_32BIT_MSB_FIRST(realauthdata+8+buflen, t); |
8def70c3 |
768 | des_encrypt_xdmauth(pr->disp->localauthdata+9, |
0a4022a1 |
769 | (unsigned char *)realauthdata, |
770 | realauthlen); |
771 | sfree(buf); |
2f92b717 |
772 | } |
e0e7dff8 |
773 | /* implement other auth methods here if required */ |
774 | |
775 | PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 6, authstrlen); |
776 | PUT_16BIT(pr->firstpkt[0], pr->firstpkt + 8, realauthlen); |
777 | |
778 | sk_write(s, (char *)pr->firstpkt, 12); |
779 | |
780 | if (authstrlen) { |
8def70c3 |
781 | sk_write(s, x11_authnames[pr->disp->localauthproto], |
782 | authstrlen); |
e0e7dff8 |
783 | sk_write(s, zeroes, 3 & (-authstrlen)); |
784 | } |
785 | if (realauthlen) { |
786 | sk_write(s, realauthdata, realauthlen); |
787 | sk_write(s, zeroes, 3 & (-realauthlen)); |
788 | } |
789 | } |
32874aea |
790 | pr->verified = 1; |
9c964e85 |
791 | } |
792 | |
793 | /* |
794 | * After initialisation, just copy data simply. |
795 | */ |
796 | |
5471d09a |
797 | return sk_write(s, data, len); |
9c964e85 |
798 | } |
bc06669b |
799 | |
800 | void x11_send_eof(Socket s) |
801 | { |
802 | sk_write_eof(s); |
803 | } |