8eebd221 |
1 | /* |
2 | * Network proxy abstraction in PuTTY |
3 | * |
4 | * A proxy layer, if necessary, wedges itself between the network |
5 | * code and the higher level backend. |
6 | */ |
7 | |
8 | #include <windows.h> |
9 | |
10 | #define DEFINE_PLUG_METHOD_MACROS |
11 | #include "putty.h" |
12 | #include "network.h" |
13 | #include "proxy.h" |
14 | |
15 | /* |
16 | * Call this when proxy negotiation is complete, so that this |
17 | * socket can begin working normally. |
18 | */ |
19 | void proxy_activate (Proxy_Socket p) |
20 | { |
21 | void *data; |
22 | int len; |
23 | |
8eebd221 |
24 | p->state = PROXY_STATE_ACTIVE; |
25 | |
26 | /* let's try to keep extra receive events from coming through */ |
27 | sk_set_frozen(p->sub_socket, 1); |
28 | |
0e8f4cda |
29 | /* send buffered OOB writes */ |
8eebd221 |
30 | while (bufchain_size(&p->pending_oob_output_data) > 0) { |
31 | bufchain_prefix(&p->pending_oob_output_data, &data, &len); |
32 | sk_write_oob(p->sub_socket, data, len); |
33 | bufchain_consume(&p->pending_oob_output_data, len); |
34 | } |
35 | bufchain_clear(&p->pending_oob_output_data); |
36 | |
0e8f4cda |
37 | /* send buffered normal writes */ |
8eebd221 |
38 | while (bufchain_size(&p->pending_output_data) > 0) { |
39 | bufchain_prefix(&p->pending_output_data, &data, &len); |
40 | sk_write(p->sub_socket, data, len); |
41 | bufchain_consume(&p->pending_output_data, len); |
42 | } |
43 | bufchain_clear(&p->pending_output_data); |
44 | |
0e8f4cda |
45 | /* if we were asked to flush the output during |
46 | * the proxy negotiation process, do so now. |
47 | */ |
8eebd221 |
48 | if (p->pending_flush) sk_flush(p->sub_socket); |
8eebd221 |
49 | |
0e8f4cda |
50 | /* forward buffered recv data to the backend */ |
8eebd221 |
51 | while (bufchain_size(&p->pending_input_data) > 0) { |
52 | bufchain_prefix(&p->pending_input_data, &data, &len); |
53 | plug_receive(p->plug, 0, data, len); |
54 | bufchain_consume(&p->pending_input_data, len); |
55 | } |
56 | bufchain_clear(&p->pending_input_data); |
8eebd221 |
57 | |
58 | /* now set the underlying socket to whatever freeze state they wanted */ |
59 | sk_set_frozen(p->sub_socket, p->freeze); |
8eebd221 |
60 | } |
61 | |
62 | /* basic proxy socket functions */ |
63 | |
64 | static Plug sk_proxy_plug (Socket s, Plug p) |
65 | { |
66 | Proxy_Socket ps = (Proxy_Socket) s; |
67 | Plug ret = ps->plug; |
68 | if (p) |
69 | ps->plug = p; |
70 | return ret; |
71 | } |
72 | |
73 | static void sk_proxy_close (Socket s) |
74 | { |
75 | Proxy_Socket ps = (Proxy_Socket) s; |
76 | |
8eebd221 |
77 | sk_close(ps->sub_socket); |
78 | sfree(ps); |
79 | } |
80 | |
81 | static int sk_proxy_write (Socket s, char *data, int len) |
82 | { |
83 | Proxy_Socket ps = (Proxy_Socket) s; |
84 | |
8eebd221 |
85 | if (ps->state != PROXY_STATE_ACTIVE) { |
86 | bufchain_add(&ps->pending_output_data, data, len); |
87 | return bufchain_size(&ps->pending_output_data); |
88 | } |
89 | return sk_write(ps->sub_socket, data, len); |
90 | } |
91 | |
92 | static int sk_proxy_write_oob (Socket s, char *data, int len) |
93 | { |
94 | Proxy_Socket ps = (Proxy_Socket) s; |
95 | |
8eebd221 |
96 | if (ps->state != PROXY_STATE_ACTIVE) { |
97 | bufchain_clear(&ps->pending_output_data); |
98 | bufchain_clear(&ps->pending_oob_output_data); |
99 | bufchain_add(&ps->pending_oob_output_data, data, len); |
100 | return len; |
101 | } |
102 | return sk_write_oob(ps->sub_socket, data, len); |
103 | } |
104 | |
105 | static void sk_proxy_flush (Socket s) |
106 | { |
107 | Proxy_Socket ps = (Proxy_Socket) s; |
108 | |
8eebd221 |
109 | if (ps->state != PROXY_STATE_ACTIVE) { |
110 | ps->pending_flush = 1; |
111 | return; |
112 | } |
113 | sk_flush(ps->sub_socket); |
114 | } |
115 | |
116 | static void sk_proxy_set_private_ptr (Socket s, void *ptr) |
117 | { |
118 | Proxy_Socket ps = (Proxy_Socket) s; |
119 | sk_set_private_ptr(ps->sub_socket, ptr); |
120 | } |
121 | |
122 | static void * sk_proxy_get_private_ptr (Socket s) |
123 | { |
124 | Proxy_Socket ps = (Proxy_Socket) s; |
125 | return sk_get_private_ptr(ps->sub_socket); |
126 | } |
127 | |
128 | static void sk_proxy_set_frozen (Socket s, int is_frozen) |
129 | { |
130 | Proxy_Socket ps = (Proxy_Socket) s; |
131 | |
8eebd221 |
132 | if (ps->state != PROXY_STATE_ACTIVE) { |
133 | ps->freeze = is_frozen; |
134 | return; |
135 | } |
136 | sk_set_frozen(ps->sub_socket, is_frozen); |
137 | } |
138 | |
139 | static char * sk_proxy_socket_error (Socket s) |
140 | { |
141 | Proxy_Socket ps = (Proxy_Socket) s; |
142 | if (ps->error != NULL || ps->sub_socket == NULL) { |
143 | return ps->error; |
144 | } |
145 | return sk_socket_error(ps->sub_socket); |
146 | } |
147 | |
148 | /* basic proxy plug functions */ |
149 | |
150 | static int plug_proxy_closing (Plug p, char *error_msg, |
151 | int error_code, int calling_back) |
152 | { |
153 | Proxy_Plug pp = (Proxy_Plug) p; |
154 | Proxy_Socket ps = pp->proxy_socket; |
155 | |
8eebd221 |
156 | if (ps->state != PROXY_STATE_ACTIVE) { |
157 | ps->closing_error_msg = error_msg; |
158 | ps->closing_error_code = error_code; |
159 | ps->closing_calling_back = calling_back; |
160 | return ps->negotiate(ps, PROXY_CHANGE_CLOSING); |
161 | } |
162 | return plug_closing(ps->plug, error_msg, |
163 | error_code, calling_back); |
164 | } |
165 | |
166 | static int plug_proxy_receive (Plug p, int urgent, char *data, int len) |
167 | { |
168 | Proxy_Plug pp = (Proxy_Plug) p; |
169 | Proxy_Socket ps = pp->proxy_socket; |
170 | |
8eebd221 |
171 | if (ps->state != PROXY_STATE_ACTIVE) { |
172 | /* we will lose the urgentness of this data, but since most, |
173 | * if not all, of this data will be consumed by the negotiation |
174 | * process, hopefully it won't affect the protocol above us |
175 | */ |
176 | bufchain_add(&ps->pending_input_data, data, len); |
177 | ps->receive_urgent = urgent; |
178 | ps->receive_data = data; |
179 | ps->receive_len = len; |
180 | return ps->negotiate(ps, PROXY_CHANGE_RECEIVE); |
181 | } |
182 | return plug_receive(ps->plug, urgent, data, len); |
183 | } |
184 | |
185 | static void plug_proxy_sent (Plug p, int bufsize) |
186 | { |
187 | Proxy_Plug pp = (Proxy_Plug) p; |
188 | Proxy_Socket ps = pp->proxy_socket; |
189 | |
8eebd221 |
190 | if (ps->state != PROXY_STATE_ACTIVE) { |
191 | ps->sent_bufsize = bufsize; |
192 | ps->negotiate(ps, PROXY_CHANGE_SENT); |
193 | return; |
194 | } |
195 | plug_sent(ps->plug, bufsize); |
196 | } |
197 | |
198 | static int plug_proxy_accepting (Plug p, void *sock) |
199 | { |
200 | Proxy_Plug pp = (Proxy_Plug) p; |
201 | Proxy_Socket ps = pp->proxy_socket; |
202 | |
8eebd221 |
203 | if (ps->state != PROXY_STATE_ACTIVE) { |
204 | ps->accepting_sock = sock; |
205 | return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING); |
206 | } |
207 | return plug_accepting(ps->plug, sock); |
208 | } |
209 | |
210 | static int proxy_for_destination (SockAddr addr, char * hostname, int port) |
211 | { |
212 | int s = 0, e = 0; |
213 | char hostip[64]; |
214 | int hostip_len, hostname_len; |
215 | char * exclude_list; |
216 | |
217 | /* we want a string representation of the IP address for comparisons */ |
218 | sk_getaddr(addr, hostip, 64); |
219 | |
220 | hostip_len = strlen(hostip); |
221 | hostname_len = strlen(hostname); |
222 | |
223 | exclude_list = cfg.proxy_exclude_list; |
224 | |
225 | /* now parse the exclude list, and see if either our IP |
226 | * or hostname matches anything in it. |
227 | */ |
228 | |
229 | while (exclude_list[s]) { |
230 | while (exclude_list[s] && |
231 | (isspace(exclude_list[s]) || |
232 | exclude_list[s] == ',')) s++; |
233 | |
234 | if (!exclude_list[s]) break; |
235 | |
236 | e = s; |
237 | |
238 | while (exclude_list[e] && |
239 | (isalnum(exclude_list[e]) || |
240 | exclude_list[e] == '-' || |
241 | exclude_list[e] == '.' || |
242 | exclude_list[e] == '*')) e++; |
243 | |
244 | if (exclude_list[s] == '*') { |
245 | /* wildcard at beginning of entry */ |
246 | |
247 | if (strnicmp(hostip + hostip_len - (e - s - 1), |
248 | exclude_list + s + 1, e - s - 1) == 0 || |
249 | strnicmp(hostname + hostname_len - (e - s - 1), |
250 | exclude_list + s + 1, e - s - 1) == 0) |
251 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
252 | |
253 | } else if (exclude_list[e-1] == '*') { |
254 | /* wildcard at end of entry */ |
255 | |
256 | if (strnicmp(hostip, exclude_list + s, e - s - 1) == 0 || |
257 | strnicmp(hostname, exclude_list + s, e - s - 1) == 0) |
258 | return 0; /* IP/hostname range excluded. do not use proxy. */ |
259 | |
260 | } else { |
261 | /* no wildcard at either end, so let's try an absolute |
262 | * match (ie. a specific IP) |
263 | */ |
264 | |
265 | if (stricmp(hostip, exclude_list + s) == 0) |
266 | return 0; /* IP/hostname excluded. do not use proxy. */ |
267 | if (stricmp(hostname, exclude_list + s) == 0) |
268 | return 0; /* IP/hostname excluded. do not use proxy. */ |
269 | } |
270 | |
271 | s = e; |
272 | } |
273 | |
274 | /* no matches in the exclude list, so use the proxy */ |
275 | return 1; |
276 | } |
277 | |
278 | Socket new_connection(SockAddr addr, char *hostname, |
279 | int port, int privport, |
280 | int oobinline, int nodelay, Plug plug) |
281 | { |
282 | static struct socket_function_table socket_fn_table = { |
283 | sk_proxy_plug, |
284 | sk_proxy_close, |
285 | sk_proxy_write, |
286 | sk_proxy_write_oob, |
287 | sk_proxy_flush, |
288 | sk_proxy_set_private_ptr, |
289 | sk_proxy_get_private_ptr, |
290 | sk_proxy_set_frozen, |
291 | sk_proxy_socket_error |
292 | }; |
293 | |
294 | static struct plug_function_table plug_fn_table = { |
295 | plug_proxy_closing, |
296 | plug_proxy_receive, |
297 | plug_proxy_sent, |
298 | plug_proxy_accepting |
299 | }; |
300 | |
301 | if (cfg.proxy_type != PROXY_NONE && |
302 | proxy_for_destination(addr, hostname, port)) |
303 | { |
304 | Proxy_Socket ret; |
305 | Proxy_Plug pplug; |
306 | SockAddr proxy_addr; |
307 | char * proxy_canonical_name; |
308 | |
309 | ret = smalloc(sizeof(struct Socket_proxy_tag)); |
310 | ret->fn = &socket_fn_table; |
311 | ret->plug = plug; |
312 | ret->remote_addr = addr; |
313 | ret->remote_port = port; |
314 | |
315 | bufchain_init(&ret->pending_input_data); |
316 | bufchain_init(&ret->pending_output_data); |
317 | bufchain_init(&ret->pending_oob_output_data); |
318 | |
8eebd221 |
319 | ret->sub_socket = NULL; |
320 | ret->state = PROXY_STATE_NEW; |
321 | |
322 | if (cfg.proxy_type == PROXY_HTTP) { |
323 | ret->negotiate = proxy_http_negotiate; |
324 | } else if (cfg.proxy_type == PROXY_SOCKS) { |
6971bbe7 |
325 | if (cfg.proxy_socks_version == 4) |
326 | ret->negotiate = proxy_socks4_negotiate; |
327 | else |
328 | ret->negotiate = proxy_socks5_negotiate; |
8eebd221 |
329 | } else if (cfg.proxy_type == PROXY_TELNET) { |
330 | ret->negotiate = proxy_telnet_negotiate; |
331 | } else { |
332 | ret->error = "Network error: Unknown proxy method"; |
333 | return (Socket) ret; |
334 | } |
335 | |
336 | /* create the proxy plug to map calls from the actual |
337 | * socket into our proxy socket layer */ |
338 | pplug = smalloc(sizeof(struct Plug_proxy_tag)); |
339 | pplug->fn = &plug_fn_table; |
340 | pplug->proxy_socket = ret; |
341 | |
342 | /* look-up proxy */ |
343 | proxy_addr = sk_namelookup(cfg.proxy_host, |
344 | &proxy_canonical_name); |
345 | sfree(proxy_canonical_name); |
346 | |
347 | /* create the actual socket we will be using, |
348 | * connected to our proxy server and port. |
349 | */ |
350 | ret->sub_socket = sk_new(proxy_addr, cfg.proxy_port, |
351 | privport, oobinline, |
352 | nodelay, (Plug) pplug); |
353 | if (sk_socket_error(ret->sub_socket) != NULL) |
354 | return (Socket) ret; |
355 | |
356 | sk_addr_free(proxy_addr); |
357 | |
358 | /* start the proxy negotiation process... */ |
359 | sk_set_frozen(ret->sub_socket, 0); |
360 | ret->negotiate(ret, PROXY_CHANGE_NEW); |
361 | |
362 | return (Socket) ret; |
363 | } |
364 | |
365 | /* no proxy, so just return the direct socket */ |
366 | return sk_new(addr, port, privport, oobinline, nodelay, plug); |
367 | } |
368 | |
369 | Socket new_listener(int port, Plug plug, int local_host_only) |
370 | { |
371 | /* TODO: SOCKS (and potentially others) support inbound |
372 | * TODO: connections via the proxy. support them. |
373 | */ |
374 | |
375 | return sk_newlistener(port, plug, local_host_only); |
376 | } |
377 | |
378 | /* ---------------------------------------------------------------------- |
379 | * HTTP CONNECT proxy type. |
380 | */ |
381 | |
382 | static int get_line_end (char * data, int len) |
383 | { |
384 | int off = 0; |
385 | |
386 | while (off < len) |
387 | { |
388 | if (data[off] == '\n') { |
389 | /* we have a newline */ |
390 | off++; |
391 | |
392 | /* is that the only thing on this line? */ |
393 | if (off <= 2) return off; |
394 | |
395 | /* if not, then there is the possibility that this header |
396 | * continues onto the next line, if it starts with a space |
397 | * or a tab. |
398 | */ |
399 | |
400 | if (off + 1 < len && |
401 | data[off+1] != ' ' && |
402 | data[off+1] != '\t') return off; |
403 | |
404 | /* the line does continue, so we have to keep going |
405 | * until we see an the header's "real" end of line. |
406 | */ |
407 | off++; |
408 | } |
409 | |
410 | off++; |
411 | } |
412 | |
413 | return -1; |
414 | } |
415 | |
416 | int proxy_http_negotiate (Proxy_Socket p, int change) |
417 | { |
418 | if (p->state == PROXY_STATE_NEW) { |
419 | /* we are just beginning the proxy negotiate process, |
420 | * so we'll send off the initial bits of the request. |
421 | * for this proxy method, it's just a simple HTTP |
422 | * request |
423 | */ |
0e8f4cda |
424 | char buf[256], dest[64]; |
8eebd221 |
425 | |
0e8f4cda |
426 | sk_getaddr(p->remote_addr, dest, 64); |
8eebd221 |
427 | |
428 | sprintf(buf, "CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n\r\n", |
429 | dest, p->remote_port, dest, p->remote_port); |
430 | sk_write(p->sub_socket, buf, strlen(buf)); |
431 | |
432 | p->state = 1; |
8eebd221 |
433 | return 0; |
434 | } |
435 | |
436 | if (change == PROXY_CHANGE_CLOSING) { |
437 | /* if our proxy negotiation process involves closing and opening |
438 | * new sockets, then we would want to intercept this closing |
439 | * callback when we were expecting it. if we aren't anticipating |
440 | * a socket close, then some error must have occurred. we'll |
441 | * just pass those errors up to the backend. |
442 | */ |
443 | return plug_closing(p->plug, p->closing_error_msg, |
444 | p->closing_error_code, |
445 | p->closing_calling_back); |
446 | } |
447 | |
448 | if (change == PROXY_CHANGE_SENT) { |
449 | /* some (or all) of what we wrote to the proxy was sent. |
450 | * we don't do anything new, however, until we receive the |
451 | * proxy's response. we might want to set a timer so we can |
452 | * timeout the proxy negotiation after a while... |
453 | */ |
454 | return 0; |
455 | } |
456 | |
457 | if (change == PROXY_CHANGE_ACCEPTING) { |
458 | /* we should _never_ see this, as we are using our socket to |
459 | * connect to a proxy, not accepting inbound connections. |
460 | * what should we do? close the socket with an appropriate |
461 | * error message? |
462 | */ |
463 | return plug_accepting(p->plug, p->accepting_sock); |
464 | } |
465 | |
466 | if (change == PROXY_CHANGE_RECEIVE) { |
467 | /* we have received data from the underlying socket, which |
468 | * we'll need to parse, process, and respond to appropriately. |
469 | */ |
470 | |
471 | void *data; |
472 | int len; |
473 | int eol; |
474 | |
475 | if (p->state == 1) { |
476 | |
477 | int min_ver, maj_ver, status; |
478 | |
479 | /* get the status line */ |
480 | bufchain_prefix(&p->pending_input_data, &data, &len); |
481 | eol = get_line_end(data, len); |
482 | if (eol < 0) return 1; |
483 | |
484 | sscanf((char *)data, "HTTP/%i.%i %i", &maj_ver, &min_ver, &status); |
485 | |
486 | /* remove the status line from the input buffer. */ |
487 | bufchain_consume(&p->pending_input_data, eol); |
488 | |
489 | /* TODO: we need to support Proxy-Auth headers */ |
490 | |
491 | if (status < 200 || status > 299) { |
492 | /* error */ |
493 | /* TODO: return a more specific error message, |
494 | * TODO: based on the status code. |
495 | */ |
496 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
497 | PROXY_ERROR_GENERAL, 0); |
498 | return 1; |
499 | } |
500 | |
501 | p->state = 2; |
502 | } |
503 | |
504 | if (p->state == 2) { |
505 | |
506 | /* get headers. we're done when we get a |
507 | * header of length 2, (ie. just "\r\n") |
508 | */ |
509 | |
510 | bufchain_prefix(&p->pending_input_data, &data, &len); |
511 | eol = get_line_end(data, len); |
512 | while (eol > 2) |
513 | { |
514 | /* TODO: Proxy-Auth stuff. in some cases, we will |
515 | * TODO: need to extract information from headers. |
516 | */ |
517 | bufchain_consume(&p->pending_input_data, eol); |
518 | bufchain_prefix(&p->pending_input_data, &data, &len); |
519 | eol = get_line_end(data, len); |
520 | } |
521 | |
522 | if (eol == 2) { |
523 | /* we're done */ |
524 | bufchain_consume(&p->pending_input_data, 2); |
525 | proxy_activate(p); |
526 | /* proxy activate will have dealt with |
527 | * whatever is left of the buffer */ |
528 | return 1; |
529 | } |
530 | |
531 | return 1; |
532 | } |
533 | } |
534 | |
535 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
536 | PROXY_ERROR_UNEXPECTED, 0); |
6971bbe7 |
537 | return 1; |
8eebd221 |
538 | } |
539 | |
540 | /* ---------------------------------------------------------------------- |
6971bbe7 |
541 | * SOCKS proxy type. |
8eebd221 |
542 | */ |
543 | |
6971bbe7 |
544 | /* SOCKS version 4 */ |
545 | int proxy_socks4_negotiate (Proxy_Socket p, int change) |
8eebd221 |
546 | { |
6971bbe7 |
547 | if (p->state == PROXY_CHANGE_NEW) { |
548 | |
549 | /* request format: |
550 | * version number (1 byte) = 4 |
551 | * command code (1 byte) |
552 | * 1 = CONNECT |
553 | * 2 = BIND |
554 | * dest. port (2 bytes) [network order] |
555 | * dest. address (4 bytes) |
556 | * user ID (variable length, null terminated string) |
557 | */ |
558 | |
559 | int length; |
560 | char * command; |
561 | |
562 | if (sk_addrtype(p->remote_addr) != AF_INET) { |
563 | plug_closing(p->plug, "Network error: SOCKS version 4 does not support IPv6", |
564 | PROXY_ERROR_GENERAL, 0); |
565 | return 1; |
566 | } |
567 | |
568 | length = strlen(cfg.proxy_username) + 9; |
569 | command = (char*) malloc(length); |
570 | strcpy(command + 8, cfg.proxy_username); |
571 | |
572 | command[0] = 4; /* version 4 */ |
573 | command[1] = 1; /* CONNECT command */ |
574 | |
575 | /* port */ |
576 | command[2] = (char) (p->remote_port >> 8) & 0xff; |
577 | command[3] = (char) p->remote_port & 0xff; |
578 | |
579 | /* address */ |
580 | sk_addrcopy(p->remote_addr, command + 4); |
581 | |
582 | sk_write(p->sub_socket, command, length); |
583 | free(command); |
584 | |
585 | p->state = 1; |
586 | return 0; |
587 | } |
588 | |
589 | if (change == PROXY_CHANGE_CLOSING) { |
590 | /* if our proxy negotiation process involves closing and opening |
591 | * new sockets, then we would want to intercept this closing |
592 | * callback when we were expecting it. if we aren't anticipating |
593 | * a socket close, then some error must have occurred. we'll |
594 | * just pass those errors up to the backend. |
595 | */ |
596 | return plug_closing(p->plug, p->closing_error_msg, |
597 | p->closing_error_code, |
598 | p->closing_calling_back); |
599 | } |
600 | |
601 | if (change == PROXY_CHANGE_SENT) { |
602 | /* some (or all) of what we wrote to the proxy was sent. |
603 | * we don't do anything new, however, until we receive the |
604 | * proxy's response. we might want to set a timer so we can |
605 | * timeout the proxy negotiation after a while... |
606 | */ |
607 | return 0; |
608 | } |
609 | |
610 | if (change == PROXY_CHANGE_ACCEPTING) { |
611 | /* we should _never_ see this, as we are using our socket to |
612 | * connect to a proxy, not accepting inbound connections. |
613 | * what should we do? close the socket with an appropriate |
614 | * error message? |
615 | */ |
616 | return plug_accepting(p->plug, p->accepting_sock); |
617 | } |
618 | |
619 | if (change == PROXY_CHANGE_RECEIVE) { |
620 | /* we have received data from the underlying socket, which |
621 | * we'll need to parse, process, and respond to appropriately. |
622 | */ |
623 | |
624 | if (p->state == 1) { |
625 | /* response format: |
626 | * version number (1 byte) = 4 |
627 | * reply code (1 byte) |
628 | * 90 = request granted |
629 | * 91 = request rejected or failed |
630 | * 92 = request rejected due to lack of IDENTD on client |
631 | * 93 = request rejected due to difference in user ID |
632 | * (what we sent vs. what IDENTD said) |
633 | * dest. port (2 bytes) |
634 | * dest. address (4 bytes) |
635 | */ |
636 | |
637 | char *data; |
638 | int len; |
639 | |
640 | /* get the response */ |
641 | bufchain_prefix(&p->pending_input_data, &data, &len); |
642 | |
643 | if (data[0] != 0) { |
644 | plug_closing(p->plug, "Network error: SOCKS proxy responded with " |
645 | "unexpected reply code version", |
646 | PROXY_ERROR_GENERAL, 0); |
647 | return 1; |
648 | } |
649 | |
650 | if (data[1] != 90) { |
651 | |
652 | switch (data[1]) { |
653 | case 92: |
654 | plug_closing(p->plug, "Network error: SOCKS server wanted IDENTD on client", |
655 | PROXY_ERROR_GENERAL, 0); |
656 | break; |
657 | case 93: |
658 | plug_closing(p->plug, "Network error: Username and IDENTD on client don't agree", |
659 | PROXY_ERROR_GENERAL, 0); |
660 | break; |
661 | case 91: |
662 | default: |
663 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
664 | PROXY_ERROR_GENERAL, 0); |
665 | break; |
666 | } |
667 | |
668 | return 1; |
669 | } |
670 | |
671 | /* we're done */ |
672 | proxy_activate(p); |
673 | /* proxy activate will have dealt with |
674 | * whatever is left of the buffer */ |
675 | return 1; |
676 | } |
677 | } |
678 | |
679 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
680 | PROXY_ERROR_UNEXPECTED, 0); |
681 | return 1; |
682 | } |
683 | |
684 | /* SOCKS version 5 */ |
685 | int proxy_socks5_negotiate (Proxy_Socket p, int change) |
686 | { |
687 | if (p->state == PROXY_CHANGE_NEW) { |
688 | |
689 | /* initial command: |
690 | * version number (1 byte) = 5 |
691 | * number of available authentication methods (1 byte) |
692 | * available authentication methods (1 byte * previous value) |
693 | * authentication methods: |
694 | * 0x00 = no authentication |
695 | * 0x01 = GSSAPI |
696 | * 0x02 = username/password |
697 | * 0x03 = CHAP |
698 | */ |
699 | |
700 | char command[3]; |
701 | |
702 | command[0] = 5; /* version 5 */ |
703 | command[1] = 1; /* TODO: we don't currently support any auth methods */ |
704 | command[2] = 0x00; /* no authentication */ |
705 | |
706 | sk_write(p->sub_socket, command, 3); |
707 | |
708 | p->state = 1; |
709 | return 0; |
710 | } |
711 | |
712 | if (change == PROXY_CHANGE_CLOSING) { |
713 | /* if our proxy negotiation process involves closing and opening |
714 | * new sockets, then we would want to intercept this closing |
715 | * callback when we were expecting it. if we aren't anticipating |
716 | * a socket close, then some error must have occurred. we'll |
717 | * just pass those errors up to the backend. |
718 | */ |
719 | return plug_closing(p->plug, p->closing_error_msg, |
720 | p->closing_error_code, |
721 | p->closing_calling_back); |
722 | } |
723 | |
724 | if (change == PROXY_CHANGE_SENT) { |
725 | /* some (or all) of what we wrote to the proxy was sent. |
726 | * we don't do anything new, however, until we receive the |
727 | * proxy's response. we might want to set a timer so we can |
728 | * timeout the proxy negotiation after a while... |
729 | */ |
730 | return 0; |
731 | } |
732 | |
733 | if (change == PROXY_CHANGE_ACCEPTING) { |
734 | /* we should _never_ see this, as we are using our socket to |
735 | * connect to a proxy, not accepting inbound connections. |
736 | * what should we do? close the socket with an appropriate |
737 | * error message? |
738 | */ |
739 | return plug_accepting(p->plug, p->accepting_sock); |
740 | } |
741 | |
742 | if (change == PROXY_CHANGE_RECEIVE) { |
743 | /* we have received data from the underlying socket, which |
744 | * we'll need to parse, process, and respond to appropriately. |
745 | */ |
746 | |
747 | char *data; |
748 | int len; |
749 | |
750 | if (p->state == 1) { |
751 | |
752 | /* initial response: |
753 | * version number (1 byte) = 5 |
754 | * authentication method (1 byte) |
755 | * authentication methods: |
756 | * 0x00 = no authentication |
757 | * 0x01 = GSSAPI |
758 | * 0x02 = username/password |
759 | * 0x03 = CHAP |
760 | * 0xff = no acceptable methods |
761 | */ |
762 | |
763 | /* get the response */ |
764 | bufchain_prefix(&p->pending_input_data, &data, &len); |
765 | |
766 | if (data[0] != 5) { |
767 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
768 | PROXY_ERROR_GENERAL, 0); |
769 | return 1; |
770 | } |
771 | |
772 | if (data[1] == 0x00) p->state = 2; /* no authentication needed */ |
773 | else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */ |
774 | else if (data[1] == 0x02) p->state = 5; /* username/password authentication */ |
775 | else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */ |
776 | else { |
777 | plug_closing(p->plug, "Network error: We don't support any of the SOCKS " |
778 | "server's authentication methods", |
779 | PROXY_ERROR_GENERAL, 0); |
780 | return 1; |
781 | } |
782 | } |
783 | |
784 | if (p->state == 2) { |
785 | |
786 | /* request format: |
787 | * version number (1 byte) = 5 |
788 | * command code (1 byte) |
789 | * 1 = CONNECT |
790 | * 2 = BIND |
791 | * 3 = UDP ASSOCIATE |
792 | * reserved (1 byte) = 0x00 |
793 | * address type (1 byte) |
794 | * 1 = IPv4 |
795 | * 3 = domainname (first byte has length, no terminating null) |
796 | * 4 = IPv6 |
797 | * dest. address (variable) |
798 | * dest. port (2 bytes) [network order] |
799 | */ |
800 | |
801 | char command[22]; |
802 | int len; |
803 | |
804 | if (sk_addrtype(p->remote_addr) == AF_INET) { |
805 | len = 10; |
806 | command[3] = 1; /* IPv4 */ |
807 | } else { |
808 | len = 22; |
809 | command[3] = 4; /* IPv6 */ |
810 | } |
811 | |
812 | command[0] = 5; /* version 5 */ |
813 | command[1] = 1; /* CONNECT command */ |
814 | command[2] = 0x00; |
815 | |
816 | /* address */ |
817 | sk_addrcopy(p->remote_addr, command+4); |
818 | |
819 | /* port */ |
820 | command[len-2] = (char) (p->remote_port >> 8) & 0xff; |
821 | command[len-1] = (char) p->remote_port & 0xff; |
822 | |
823 | sk_write(p->sub_socket, command, len); |
824 | |
825 | p->state = 3; |
826 | return 1; |
827 | } |
828 | |
829 | if (p->state == 3) { |
830 | |
831 | /* reply format: |
832 | * version number (1 bytes) = 5 |
833 | * reply code (1 byte) |
834 | * 0 = succeeded |
835 | * 1 = general SOCKS server failure |
836 | * 2 = connection not allowed by ruleset |
837 | * 3 = network unreachable |
838 | * 4 = host unreachable |
839 | * 5 = connection refused |
840 | * 6 = TTL expired |
841 | * 7 = command not supported |
842 | * 8 = address type not supported |
843 | * reserved (1 byte) = x00 |
844 | * address type (1 byte) |
845 | * 1 = IPv4 |
846 | * 3 = domainname (first byte has length, no terminating null) |
847 | * 4 = IPv6 |
848 | * server bound address (variable) |
849 | * server bound port (2 bytes) [network order] |
850 | */ |
851 | |
852 | /* get the response */ |
853 | bufchain_prefix(&p->pending_input_data, &data, &len); |
854 | |
855 | if (data[0] != 5) { |
856 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
857 | PROXY_ERROR_GENERAL, 0); |
858 | return 1; |
859 | } |
860 | |
861 | if (data[1] != 0) { |
862 | |
863 | switch (data[1]) { |
864 | case 1: |
865 | case 2: |
866 | case 3: |
867 | case 4: |
868 | case 5: |
869 | case 6: |
870 | case 7: |
871 | case 8: |
872 | default: |
873 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
874 | PROXY_ERROR_GENERAL, 0); |
875 | break; |
876 | } |
877 | |
878 | return 1; |
879 | } |
880 | |
881 | /* we're done */ |
882 | proxy_activate(p); |
883 | /* proxy activate will have dealt with |
884 | * whatever is left of the buffer */ |
885 | return 1; |
886 | } |
887 | |
888 | if (p->state == 4) { |
889 | /* TODO: Handle GSSAPI authentication */ |
890 | plug_closing(p->plug, "Network error: We don't support GSSAPI authentication", |
891 | PROXY_ERROR_GENERAL, 0); |
892 | return 1; |
893 | } |
894 | |
895 | if (p->state == 5) { |
896 | /* TODO: Handle username/password authentication */ |
897 | plug_closing(p->plug, "Network error: We don't support username/password " |
898 | "authentication", |
899 | PROXY_ERROR_GENERAL, 0); |
900 | return 1; |
901 | } |
902 | |
903 | if (p->state == 6) { |
904 | /* TODO: Handle CHAP authentication */ |
905 | plug_closing(p->plug, "Network error: We don't support CHAP authentication", |
906 | PROXY_ERROR_GENERAL, 0); |
907 | return 1; |
908 | } |
909 | } |
910 | |
911 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
912 | PROXY_ERROR_UNEXPECTED, 0); |
913 | return 1; |
8eebd221 |
914 | } |
915 | |
916 | /* ---------------------------------------------------------------------- |
0e8f4cda |
917 | * `Telnet' proxy type. |
8eebd221 |
918 | * |
919 | * (This is for ad-hoc proxies where you connect to the proxy's |
920 | * telnet port and send a command such as `connect host port'. The |
921 | * command is configurable, since this proxy type is typically not |
922 | * standardised or at all well-defined.) |
923 | */ |
924 | |
925 | int proxy_telnet_negotiate (Proxy_Socket p, int change) |
926 | { |
0e8f4cda |
927 | if (p->state == PROXY_CHANGE_NEW) { |
928 | |
929 | int so = 0, eo = 0; |
930 | |
931 | /* we need to escape \\, \%, \r, \n, \t, \x??, \0???, |
932 | * %%, %host, and %port |
933 | */ |
934 | |
935 | while (cfg.proxy_telnet_command[eo] != 0) { |
936 | |
937 | /* scan forward until we hit end-of-line, |
938 | * or an escape character (\ or %) */ |
939 | while (cfg.proxy_telnet_command[eo] != 0 && |
940 | cfg.proxy_telnet_command[eo] != '%' && |
941 | cfg.proxy_telnet_command[eo] != '\\') eo++; |
942 | |
943 | /* if we hit eol, break out of our escaping loop */ |
944 | if (cfg.proxy_telnet_command[eo] == 0) break; |
945 | |
946 | /* if there was any unescaped text before the escape |
947 | * character, send that now */ |
948 | if (eo != so) { |
949 | sk_write(p->sub_socket, |
950 | cfg.proxy_telnet_command + so, eo - so); |
951 | } |
952 | |
953 | so = eo++; |
954 | |
955 | /* if the escape character was the last character of |
956 | * the line, we'll just stop and send it. */ |
957 | if (cfg.proxy_telnet_command[eo] == 0) break; |
958 | |
959 | if (cfg.proxy_telnet_command[so] == '\\') { |
960 | |
961 | /* we recognize \\, \%, \r, \n, \t, \x??. |
962 | * anything else, we just send unescaped (including the \). |
963 | */ |
964 | |
965 | switch (cfg.proxy_telnet_command[eo]) { |
966 | |
967 | case '\\': |
968 | sk_write(p->sub_socket, "\\", 1); |
969 | eo++; |
970 | break; |
971 | |
972 | case '%': |
973 | sk_write(p->sub_socket, "%%", 1); |
974 | eo++; |
975 | break; |
976 | |
977 | case 'r': |
978 | sk_write(p->sub_socket, "\r", 1); |
979 | eo++; |
980 | break; |
981 | |
982 | case 'n': |
983 | sk_write(p->sub_socket, "\n", 1); |
984 | eo++; |
985 | break; |
986 | |
987 | case 't': |
988 | sk_write(p->sub_socket, "\t", 1); |
989 | eo++; |
990 | break; |
991 | |
992 | case 'x': |
993 | case 'X': |
994 | { |
995 | /* escaped hexadecimal value (ie. \xff) */ |
996 | unsigned char v = 0; |
997 | int i = 0; |
998 | |
999 | for (;;) { |
1000 | eo++; |
1001 | if (cfg.proxy_telnet_command[eo] >= '0' && |
1002 | cfg.proxy_telnet_command[eo] <= '9') |
1003 | v += cfg.proxy_telnet_command[eo] - '0'; |
1004 | else if (cfg.proxy_telnet_command[eo] >= 'a' && |
1005 | cfg.proxy_telnet_command[eo] <= 'f') |
1006 | v += cfg.proxy_telnet_command[eo] - 'a' + 10; |
1007 | else if (cfg.proxy_telnet_command[eo] >= 'A' && |
1008 | cfg.proxy_telnet_command[eo] <= 'F') |
1009 | v += cfg.proxy_telnet_command[eo] - 'A' + 10; |
1010 | else { |
1011 | /* non hex character, so we abort and just |
1012 | * send the whole thing unescaped (including \x) |
1013 | */ |
1014 | sk_write(p->sub_socket, "\\", 1); |
1015 | eo = so + 1; |
1016 | break; |
1017 | } |
1018 | |
1019 | /* we only extract two hex characters */ |
1020 | if (i == 1) { |
1021 | sk_write(p->sub_socket, &v, 1); |
1022 | eo++; |
1023 | break; |
1024 | } |
1025 | |
1026 | i++; |
1027 | v <<= 4; |
1028 | } |
1029 | } |
1030 | break; |
1031 | |
1032 | default: |
1033 | sk_write(p->sub_socket, |
1034 | cfg.proxy_telnet_command + so, 2); |
1035 | eo++; |
1036 | break; |
1037 | } |
1038 | } else { |
1039 | |
1040 | /* % escape. we recognize %%, %host, %port. anything else, |
1041 | * we just send unescaped (including the %). */ |
1042 | |
1043 | if (cfg.proxy_telnet_command[eo] == '%') { |
1044 | sk_write(p->sub_socket, "%", 1); |
1045 | eo++; |
1046 | } |
1047 | else if (strnicmp(cfg.proxy_telnet_command + eo, |
1048 | "host", 4) == 0) { |
1049 | char dest[64]; |
1050 | sk_getaddr(p->remote_addr, dest, 64); |
1051 | sk_write(p->sub_socket, dest, strlen(dest)); |
1052 | eo += 4; |
1053 | } |
1054 | else if (strnicmp(cfg.proxy_telnet_command + eo, |
1055 | "port", 4) == 0) { |
1056 | char port[8]; |
1057 | sprintf(port, "%i", p->remote_port); |
1058 | sk_write(p->sub_socket, port, strlen(port)); |
1059 | eo += 4; |
1060 | } |
1061 | else { |
1062 | /* we don't escape this, so send the % now, and |
1063 | * don't advance eo, so that we'll consider the |
1064 | * text immediately following the % as unescaped. |
1065 | */ |
1066 | sk_write(p->sub_socket, "%", 1); |
1067 | } |
1068 | } |
1069 | |
1070 | /* resume scanning for additional escapes after this one. */ |
1071 | so = eo; |
1072 | } |
1073 | |
1074 | /* if there is any unescaped text at the end of the line, send it */ |
1075 | if (eo != so) { |
1076 | sk_write(p->sub_socket, cfg.proxy_telnet_command + so, eo - so); |
1077 | } |
1078 | |
1079 | p->state = 1; |
0e8f4cda |
1080 | return 0; |
1081 | } |
1082 | |
1083 | if (change == PROXY_CHANGE_CLOSING) { |
1084 | /* if our proxy negotiation process involves closing and opening |
1085 | * new sockets, then we would want to intercept this closing |
1086 | * callback when we were expecting it. if we aren't anticipating |
1087 | * a socket close, then some error must have occurred. we'll |
1088 | * just pass those errors up to the backend. |
1089 | */ |
1090 | return plug_closing(p->plug, p->closing_error_msg, |
1091 | p->closing_error_code, |
1092 | p->closing_calling_back); |
1093 | } |
1094 | |
1095 | if (change == PROXY_CHANGE_SENT) { |
1096 | /* some (or all) of what we wrote to the proxy was sent. |
1097 | * we don't do anything new, however, until we receive the |
1098 | * proxy's response. we might want to set a timer so we can |
1099 | * timeout the proxy negotiation after a while... |
1100 | */ |
1101 | return 0; |
1102 | } |
1103 | |
1104 | if (change == PROXY_CHANGE_ACCEPTING) { |
1105 | /* we should _never_ see this, as we are using our socket to |
1106 | * connect to a proxy, not accepting inbound connections. |
1107 | * what should we do? close the socket with an appropriate |
1108 | * error message? |
1109 | */ |
1110 | return plug_accepting(p->plug, p->accepting_sock); |
1111 | } |
1112 | |
1113 | if (change == PROXY_CHANGE_RECEIVE) { |
1114 | /* we have received data from the underlying socket, which |
1115 | * we'll need to parse, process, and respond to appropriately. |
1116 | */ |
1117 | |
1118 | /* we're done */ |
1119 | proxy_activate(p); |
1120 | /* proxy activate will have dealt with |
1121 | * whatever is left of the buffer */ |
1122 | return 1; |
1123 | } |
1124 | |
1125 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
1126 | PROXY_ERROR_UNEXPECTED, 0); |
6971bbe7 |
1127 | return 1; |
8eebd221 |
1128 | } |