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 | |
1549e076 |
428 | sprintf(buf, "CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n", |
8eebd221 |
429 | dest, p->remote_port, dest, p->remote_port); |
430 | sk_write(p->sub_socket, buf, strlen(buf)); |
431 | |
1549e076 |
432 | if (cfg.proxy_username[0] || cfg.proxy_password[0]) { |
433 | char buf[sizeof(cfg.proxy_username)+sizeof(cfg.proxy_password)]; |
434 | char buf2[sizeof(buf)*4/3 + 100]; |
435 | int i, j, len; |
436 | sprintf(buf, "%s:%s", cfg.proxy_username, cfg.proxy_password); |
437 | len = strlen(buf); |
438 | sprintf(buf2, "Proxy-Authorization: basic "); |
439 | for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4) |
440 | base64_encode_atom(buf+i, (len-i > 3 ? 3 : len-i), buf2+j); |
441 | strcpy(buf2+j, "\r\n"); |
442 | sk_write(p->sub_socket, buf2, strlen(buf2)); |
443 | } |
444 | |
445 | sprintf(buf, "\r\n"); |
446 | sk_write(p->sub_socket, buf, strlen(buf)); |
447 | |
8eebd221 |
448 | p->state = 1; |
8eebd221 |
449 | return 0; |
450 | } |
451 | |
452 | if (change == PROXY_CHANGE_CLOSING) { |
453 | /* if our proxy negotiation process involves closing and opening |
454 | * new sockets, then we would want to intercept this closing |
455 | * callback when we were expecting it. if we aren't anticipating |
456 | * a socket close, then some error must have occurred. we'll |
457 | * just pass those errors up to the backend. |
458 | */ |
459 | return plug_closing(p->plug, p->closing_error_msg, |
460 | p->closing_error_code, |
461 | p->closing_calling_back); |
462 | } |
463 | |
464 | if (change == PROXY_CHANGE_SENT) { |
465 | /* some (or all) of what we wrote to the proxy was sent. |
466 | * we don't do anything new, however, until we receive the |
467 | * proxy's response. we might want to set a timer so we can |
468 | * timeout the proxy negotiation after a while... |
469 | */ |
470 | return 0; |
471 | } |
472 | |
473 | if (change == PROXY_CHANGE_ACCEPTING) { |
474 | /* we should _never_ see this, as we are using our socket to |
475 | * connect to a proxy, not accepting inbound connections. |
476 | * what should we do? close the socket with an appropriate |
477 | * error message? |
478 | */ |
479 | return plug_accepting(p->plug, p->accepting_sock); |
480 | } |
481 | |
482 | if (change == PROXY_CHANGE_RECEIVE) { |
483 | /* we have received data from the underlying socket, which |
484 | * we'll need to parse, process, and respond to appropriately. |
485 | */ |
486 | |
487 | void *data; |
488 | int len; |
489 | int eol; |
490 | |
491 | if (p->state == 1) { |
492 | |
493 | int min_ver, maj_ver, status; |
494 | |
495 | /* get the status line */ |
496 | bufchain_prefix(&p->pending_input_data, &data, &len); |
497 | eol = get_line_end(data, len); |
498 | if (eol < 0) return 1; |
499 | |
500 | sscanf((char *)data, "HTTP/%i.%i %i", &maj_ver, &min_ver, &status); |
501 | |
502 | /* remove the status line from the input buffer. */ |
503 | bufchain_consume(&p->pending_input_data, eol); |
504 | |
505 | /* TODO: we need to support Proxy-Auth headers */ |
506 | |
507 | if (status < 200 || status > 299) { |
508 | /* error */ |
509 | /* TODO: return a more specific error message, |
510 | * TODO: based on the status code. |
511 | */ |
512 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
513 | PROXY_ERROR_GENERAL, 0); |
514 | return 1; |
515 | } |
516 | |
517 | p->state = 2; |
518 | } |
519 | |
520 | if (p->state == 2) { |
521 | |
522 | /* get headers. we're done when we get a |
523 | * header of length 2, (ie. just "\r\n") |
524 | */ |
525 | |
526 | bufchain_prefix(&p->pending_input_data, &data, &len); |
527 | eol = get_line_end(data, len); |
528 | while (eol > 2) |
529 | { |
530 | /* TODO: Proxy-Auth stuff. in some cases, we will |
531 | * TODO: need to extract information from headers. |
532 | */ |
533 | bufchain_consume(&p->pending_input_data, eol); |
534 | bufchain_prefix(&p->pending_input_data, &data, &len); |
535 | eol = get_line_end(data, len); |
536 | } |
537 | |
538 | if (eol == 2) { |
539 | /* we're done */ |
540 | bufchain_consume(&p->pending_input_data, 2); |
541 | proxy_activate(p); |
542 | /* proxy activate will have dealt with |
543 | * whatever is left of the buffer */ |
544 | return 1; |
545 | } |
546 | |
547 | return 1; |
548 | } |
549 | } |
550 | |
551 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
552 | PROXY_ERROR_UNEXPECTED, 0); |
6971bbe7 |
553 | return 1; |
8eebd221 |
554 | } |
555 | |
556 | /* ---------------------------------------------------------------------- |
6971bbe7 |
557 | * SOCKS proxy type. |
8eebd221 |
558 | */ |
559 | |
6971bbe7 |
560 | /* SOCKS version 4 */ |
561 | int proxy_socks4_negotiate (Proxy_Socket p, int change) |
8eebd221 |
562 | { |
6971bbe7 |
563 | if (p->state == PROXY_CHANGE_NEW) { |
564 | |
565 | /* request format: |
566 | * version number (1 byte) = 4 |
567 | * command code (1 byte) |
568 | * 1 = CONNECT |
569 | * 2 = BIND |
570 | * dest. port (2 bytes) [network order] |
571 | * dest. address (4 bytes) |
572 | * user ID (variable length, null terminated string) |
573 | */ |
574 | |
575 | int length; |
576 | char * command; |
577 | |
578 | if (sk_addrtype(p->remote_addr) != AF_INET) { |
579 | plug_closing(p->plug, "Network error: SOCKS version 4 does not support IPv6", |
580 | PROXY_ERROR_GENERAL, 0); |
581 | return 1; |
582 | } |
583 | |
584 | length = strlen(cfg.proxy_username) + 9; |
585 | command = (char*) malloc(length); |
586 | strcpy(command + 8, cfg.proxy_username); |
587 | |
588 | command[0] = 4; /* version 4 */ |
589 | command[1] = 1; /* CONNECT command */ |
590 | |
591 | /* port */ |
592 | command[2] = (char) (p->remote_port >> 8) & 0xff; |
593 | command[3] = (char) p->remote_port & 0xff; |
594 | |
595 | /* address */ |
596 | sk_addrcopy(p->remote_addr, command + 4); |
597 | |
598 | sk_write(p->sub_socket, command, length); |
599 | free(command); |
600 | |
601 | p->state = 1; |
602 | return 0; |
603 | } |
604 | |
605 | if (change == PROXY_CHANGE_CLOSING) { |
606 | /* if our proxy negotiation process involves closing and opening |
607 | * new sockets, then we would want to intercept this closing |
608 | * callback when we were expecting it. if we aren't anticipating |
609 | * a socket close, then some error must have occurred. we'll |
610 | * just pass those errors up to the backend. |
611 | */ |
612 | return plug_closing(p->plug, p->closing_error_msg, |
613 | p->closing_error_code, |
614 | p->closing_calling_back); |
615 | } |
616 | |
617 | if (change == PROXY_CHANGE_SENT) { |
618 | /* some (or all) of what we wrote to the proxy was sent. |
619 | * we don't do anything new, however, until we receive the |
620 | * proxy's response. we might want to set a timer so we can |
621 | * timeout the proxy negotiation after a while... |
622 | */ |
623 | return 0; |
624 | } |
625 | |
626 | if (change == PROXY_CHANGE_ACCEPTING) { |
627 | /* we should _never_ see this, as we are using our socket to |
628 | * connect to a proxy, not accepting inbound connections. |
629 | * what should we do? close the socket with an appropriate |
630 | * error message? |
631 | */ |
632 | return plug_accepting(p->plug, p->accepting_sock); |
633 | } |
634 | |
635 | if (change == PROXY_CHANGE_RECEIVE) { |
636 | /* we have received data from the underlying socket, which |
637 | * we'll need to parse, process, and respond to appropriately. |
638 | */ |
639 | |
640 | if (p->state == 1) { |
641 | /* response format: |
642 | * version number (1 byte) = 4 |
643 | * reply code (1 byte) |
644 | * 90 = request granted |
645 | * 91 = request rejected or failed |
646 | * 92 = request rejected due to lack of IDENTD on client |
647 | * 93 = request rejected due to difference in user ID |
648 | * (what we sent vs. what IDENTD said) |
649 | * dest. port (2 bytes) |
650 | * dest. address (4 bytes) |
651 | */ |
652 | |
653 | char *data; |
654 | int len; |
655 | |
656 | /* get the response */ |
657 | bufchain_prefix(&p->pending_input_data, &data, &len); |
658 | |
659 | if (data[0] != 0) { |
660 | plug_closing(p->plug, "Network error: SOCKS proxy responded with " |
661 | "unexpected reply code version", |
662 | PROXY_ERROR_GENERAL, 0); |
663 | return 1; |
664 | } |
665 | |
666 | if (data[1] != 90) { |
667 | |
668 | switch (data[1]) { |
669 | case 92: |
670 | plug_closing(p->plug, "Network error: SOCKS server wanted IDENTD on client", |
671 | PROXY_ERROR_GENERAL, 0); |
672 | break; |
673 | case 93: |
674 | plug_closing(p->plug, "Network error: Username and IDENTD on client don't agree", |
675 | PROXY_ERROR_GENERAL, 0); |
676 | break; |
677 | case 91: |
678 | default: |
679 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
680 | PROXY_ERROR_GENERAL, 0); |
681 | break; |
682 | } |
683 | |
684 | return 1; |
685 | } |
aab91a3e |
686 | bufchain_consume(&p->pending_input_data, 2); |
6971bbe7 |
687 | |
688 | /* we're done */ |
689 | proxy_activate(p); |
690 | /* proxy activate will have dealt with |
691 | * whatever is left of the buffer */ |
692 | return 1; |
693 | } |
694 | } |
695 | |
696 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
697 | PROXY_ERROR_UNEXPECTED, 0); |
698 | return 1; |
699 | } |
700 | |
701 | /* SOCKS version 5 */ |
702 | int proxy_socks5_negotiate (Proxy_Socket p, int change) |
703 | { |
704 | if (p->state == PROXY_CHANGE_NEW) { |
705 | |
706 | /* initial command: |
707 | * version number (1 byte) = 5 |
708 | * number of available authentication methods (1 byte) |
709 | * available authentication methods (1 byte * previous value) |
710 | * authentication methods: |
711 | * 0x00 = no authentication |
712 | * 0x01 = GSSAPI |
713 | * 0x02 = username/password |
714 | * 0x03 = CHAP |
715 | */ |
716 | |
aab91a3e |
717 | char command[4]; |
718 | int len; |
6971bbe7 |
719 | |
720 | command[0] = 5; /* version 5 */ |
aab91a3e |
721 | if (cfg.proxy_username[0] || cfg.proxy_password[0]) { |
722 | command[1] = 2; /* two methods supported: */ |
723 | command[2] = 0x00; /* no authentication */ |
724 | command[3] = 0x02; /* username/password */ |
725 | len = 4; |
726 | } else { |
727 | command[1] = 1; /* one methods supported: */ |
728 | command[2] = 0x00; /* no authentication */ |
729 | len = 3; |
730 | } |
6971bbe7 |
731 | |
aab91a3e |
732 | sk_write(p->sub_socket, command, len); |
6971bbe7 |
733 | |
734 | p->state = 1; |
735 | return 0; |
736 | } |
737 | |
738 | if (change == PROXY_CHANGE_CLOSING) { |
739 | /* if our proxy negotiation process involves closing and opening |
740 | * new sockets, then we would want to intercept this closing |
741 | * callback when we were expecting it. if we aren't anticipating |
742 | * a socket close, then some error must have occurred. we'll |
743 | * just pass those errors up to the backend. |
744 | */ |
745 | return plug_closing(p->plug, p->closing_error_msg, |
746 | p->closing_error_code, |
747 | p->closing_calling_back); |
748 | } |
749 | |
750 | if (change == PROXY_CHANGE_SENT) { |
751 | /* some (or all) of what we wrote to the proxy was sent. |
752 | * we don't do anything new, however, until we receive the |
753 | * proxy's response. we might want to set a timer so we can |
754 | * timeout the proxy negotiation after a while... |
755 | */ |
756 | return 0; |
757 | } |
758 | |
759 | if (change == PROXY_CHANGE_ACCEPTING) { |
760 | /* we should _never_ see this, as we are using our socket to |
761 | * connect to a proxy, not accepting inbound connections. |
762 | * what should we do? close the socket with an appropriate |
763 | * error message? |
764 | */ |
765 | return plug_accepting(p->plug, p->accepting_sock); |
766 | } |
767 | |
768 | if (change == PROXY_CHANGE_RECEIVE) { |
769 | /* we have received data from the underlying socket, which |
770 | * we'll need to parse, process, and respond to appropriately. |
771 | */ |
772 | |
773 | char *data; |
774 | int len; |
775 | |
776 | if (p->state == 1) { |
777 | |
778 | /* initial response: |
779 | * version number (1 byte) = 5 |
780 | * authentication method (1 byte) |
781 | * authentication methods: |
782 | * 0x00 = no authentication |
783 | * 0x01 = GSSAPI |
784 | * 0x02 = username/password |
785 | * 0x03 = CHAP |
786 | * 0xff = no acceptable methods |
787 | */ |
788 | |
789 | /* get the response */ |
790 | bufchain_prefix(&p->pending_input_data, &data, &len); |
791 | |
792 | if (data[0] != 5) { |
793 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
794 | PROXY_ERROR_GENERAL, 0); |
795 | return 1; |
796 | } |
797 | |
798 | if (data[1] == 0x00) p->state = 2; /* no authentication needed */ |
799 | else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */ |
800 | else if (data[1] == 0x02) p->state = 5; /* username/password authentication */ |
801 | else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */ |
802 | else { |
803 | plug_closing(p->plug, "Network error: We don't support any of the SOCKS " |
804 | "server's authentication methods", |
805 | PROXY_ERROR_GENERAL, 0); |
806 | return 1; |
807 | } |
aab91a3e |
808 | bufchain_consume(&p->pending_input_data, 2); |
809 | } |
810 | |
811 | if (p->state == 7) { |
812 | |
813 | /* password authentication reply format: |
814 | * version number (1 bytes) = 1 |
815 | * reply code (1 byte) |
816 | * 0 = succeeded |
817 | * >0 = failed |
818 | */ |
819 | |
820 | /* get the response */ |
821 | bufchain_prefix(&p->pending_input_data, &data, &len); |
822 | |
823 | if (data[0] != 1) { |
824 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
825 | PROXY_ERROR_GENERAL, 0); |
826 | return 1; |
827 | } |
828 | |
829 | if (data[1] != 0) { |
830 | |
831 | plug_closing(p->plug, "Network error: Proxy refused authentication", |
832 | PROXY_ERROR_GENERAL, 0); |
833 | return 1; |
834 | } |
835 | |
836 | bufchain_consume(&p->pending_input_data, 2); |
837 | p->state = 2; /* now proceed as authenticated */ |
6971bbe7 |
838 | } |
839 | |
840 | if (p->state == 2) { |
841 | |
842 | /* request format: |
843 | * version number (1 byte) = 5 |
844 | * command code (1 byte) |
845 | * 1 = CONNECT |
846 | * 2 = BIND |
847 | * 3 = UDP ASSOCIATE |
848 | * reserved (1 byte) = 0x00 |
849 | * address type (1 byte) |
850 | * 1 = IPv4 |
851 | * 3 = domainname (first byte has length, no terminating null) |
852 | * 4 = IPv6 |
853 | * dest. address (variable) |
854 | * dest. port (2 bytes) [network order] |
855 | */ |
856 | |
857 | char command[22]; |
858 | int len; |
859 | |
860 | if (sk_addrtype(p->remote_addr) == AF_INET) { |
861 | len = 10; |
862 | command[3] = 1; /* IPv4 */ |
863 | } else { |
864 | len = 22; |
865 | command[3] = 4; /* IPv6 */ |
866 | } |
867 | |
868 | command[0] = 5; /* version 5 */ |
869 | command[1] = 1; /* CONNECT command */ |
870 | command[2] = 0x00; |
871 | |
872 | /* address */ |
873 | sk_addrcopy(p->remote_addr, command+4); |
874 | |
875 | /* port */ |
876 | command[len-2] = (char) (p->remote_port >> 8) & 0xff; |
877 | command[len-1] = (char) p->remote_port & 0xff; |
878 | |
879 | sk_write(p->sub_socket, command, len); |
880 | |
881 | p->state = 3; |
882 | return 1; |
883 | } |
884 | |
885 | if (p->state == 3) { |
886 | |
887 | /* reply format: |
888 | * version number (1 bytes) = 5 |
889 | * reply code (1 byte) |
890 | * 0 = succeeded |
891 | * 1 = general SOCKS server failure |
892 | * 2 = connection not allowed by ruleset |
893 | * 3 = network unreachable |
894 | * 4 = host unreachable |
895 | * 5 = connection refused |
896 | * 6 = TTL expired |
897 | * 7 = command not supported |
898 | * 8 = address type not supported |
899 | * reserved (1 byte) = x00 |
900 | * address type (1 byte) |
901 | * 1 = IPv4 |
902 | * 3 = domainname (first byte has length, no terminating null) |
903 | * 4 = IPv6 |
904 | * server bound address (variable) |
905 | * server bound port (2 bytes) [network order] |
906 | */ |
907 | |
908 | /* get the response */ |
909 | bufchain_prefix(&p->pending_input_data, &data, &len); |
910 | |
911 | if (data[0] != 5) { |
912 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
913 | PROXY_ERROR_GENERAL, 0); |
914 | return 1; |
915 | } |
916 | |
917 | if (data[1] != 0) { |
918 | |
919 | switch (data[1]) { |
920 | case 1: |
921 | case 2: |
922 | case 3: |
923 | case 4: |
924 | case 5: |
925 | case 6: |
926 | case 7: |
927 | case 8: |
928 | default: |
929 | plug_closing(p->plug, "Network error: Error while communicating with proxy", |
930 | PROXY_ERROR_GENERAL, 0); |
931 | break; |
932 | } |
933 | |
934 | return 1; |
935 | } |
936 | |
937 | /* we're done */ |
938 | proxy_activate(p); |
939 | /* proxy activate will have dealt with |
940 | * whatever is left of the buffer */ |
941 | return 1; |
942 | } |
943 | |
944 | if (p->state == 4) { |
945 | /* TODO: Handle GSSAPI authentication */ |
946 | plug_closing(p->plug, "Network error: We don't support GSSAPI authentication", |
947 | PROXY_ERROR_GENERAL, 0); |
948 | return 1; |
949 | } |
950 | |
951 | if (p->state == 5) { |
aab91a3e |
952 | if (cfg.proxy_username[0] || cfg.proxy_password[0]) { |
953 | char userpwbuf[514]; |
954 | int ulen, plen; |
955 | ulen = strlen(cfg.proxy_username); |
956 | if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1; |
957 | plen = strlen(cfg.proxy_password); |
958 | if (plen > 255) plen = 255; if (plen < 1) plen = 1; |
959 | userpwbuf[0] = 1; /* version number of subnegotiation */ |
960 | userpwbuf[1] = ulen; |
961 | memcpy(userpwbuf+2, cfg.proxy_username, ulen); |
962 | userpwbuf[ulen+2] = plen; |
963 | memcpy(userpwbuf+ulen+3, cfg.proxy_password, plen); |
964 | sk_write(p->sub_socket, userpwbuf, ulen + plen + 3); |
965 | p->state = 7; |
966 | } else |
967 | plug_closing(p->plug, "Network error: Server chose " |
968 | "username/password authentication but we " |
969 | "didn't offer it!", |
6971bbe7 |
970 | PROXY_ERROR_GENERAL, 0); |
971 | return 1; |
972 | } |
973 | |
974 | if (p->state == 6) { |
975 | /* TODO: Handle CHAP authentication */ |
976 | plug_closing(p->plug, "Network error: We don't support CHAP authentication", |
977 | PROXY_ERROR_GENERAL, 0); |
978 | return 1; |
979 | } |
aab91a3e |
980 | |
6971bbe7 |
981 | } |
982 | |
983 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
984 | PROXY_ERROR_UNEXPECTED, 0); |
985 | return 1; |
8eebd221 |
986 | } |
987 | |
988 | /* ---------------------------------------------------------------------- |
0e8f4cda |
989 | * `Telnet' proxy type. |
8eebd221 |
990 | * |
991 | * (This is for ad-hoc proxies where you connect to the proxy's |
992 | * telnet port and send a command such as `connect host port'. The |
993 | * command is configurable, since this proxy type is typically not |
994 | * standardised or at all well-defined.) |
995 | */ |
996 | |
997 | int proxy_telnet_negotiate (Proxy_Socket p, int change) |
998 | { |
0e8f4cda |
999 | if (p->state == PROXY_CHANGE_NEW) { |
1000 | |
1001 | int so = 0, eo = 0; |
1002 | |
1003 | /* we need to escape \\, \%, \r, \n, \t, \x??, \0???, |
1004 | * %%, %host, and %port |
1005 | */ |
1006 | |
1007 | while (cfg.proxy_telnet_command[eo] != 0) { |
1008 | |
1009 | /* scan forward until we hit end-of-line, |
1010 | * or an escape character (\ or %) */ |
1011 | while (cfg.proxy_telnet_command[eo] != 0 && |
1012 | cfg.proxy_telnet_command[eo] != '%' && |
1013 | cfg.proxy_telnet_command[eo] != '\\') eo++; |
1014 | |
1015 | /* if we hit eol, break out of our escaping loop */ |
1016 | if (cfg.proxy_telnet_command[eo] == 0) break; |
1017 | |
1018 | /* if there was any unescaped text before the escape |
1019 | * character, send that now */ |
1020 | if (eo != so) { |
1021 | sk_write(p->sub_socket, |
1022 | cfg.proxy_telnet_command + so, eo - so); |
1023 | } |
1024 | |
1025 | so = eo++; |
1026 | |
1027 | /* if the escape character was the last character of |
1028 | * the line, we'll just stop and send it. */ |
1029 | if (cfg.proxy_telnet_command[eo] == 0) break; |
1030 | |
1031 | if (cfg.proxy_telnet_command[so] == '\\') { |
1032 | |
1033 | /* we recognize \\, \%, \r, \n, \t, \x??. |
1034 | * anything else, we just send unescaped (including the \). |
1035 | */ |
1036 | |
1037 | switch (cfg.proxy_telnet_command[eo]) { |
1038 | |
1039 | case '\\': |
1040 | sk_write(p->sub_socket, "\\", 1); |
1041 | eo++; |
1042 | break; |
1043 | |
1044 | case '%': |
1045 | sk_write(p->sub_socket, "%%", 1); |
1046 | eo++; |
1047 | break; |
1048 | |
1049 | case 'r': |
1050 | sk_write(p->sub_socket, "\r", 1); |
1051 | eo++; |
1052 | break; |
1053 | |
1054 | case 'n': |
1055 | sk_write(p->sub_socket, "\n", 1); |
1056 | eo++; |
1057 | break; |
1058 | |
1059 | case 't': |
1060 | sk_write(p->sub_socket, "\t", 1); |
1061 | eo++; |
1062 | break; |
1063 | |
1064 | case 'x': |
1065 | case 'X': |
1066 | { |
1067 | /* escaped hexadecimal value (ie. \xff) */ |
1068 | unsigned char v = 0; |
1069 | int i = 0; |
1070 | |
1071 | for (;;) { |
1072 | eo++; |
1073 | if (cfg.proxy_telnet_command[eo] >= '0' && |
1074 | cfg.proxy_telnet_command[eo] <= '9') |
1075 | v += cfg.proxy_telnet_command[eo] - '0'; |
1076 | else if (cfg.proxy_telnet_command[eo] >= 'a' && |
1077 | cfg.proxy_telnet_command[eo] <= 'f') |
1078 | v += cfg.proxy_telnet_command[eo] - 'a' + 10; |
1079 | else if (cfg.proxy_telnet_command[eo] >= 'A' && |
1080 | cfg.proxy_telnet_command[eo] <= 'F') |
1081 | v += cfg.proxy_telnet_command[eo] - 'A' + 10; |
1082 | else { |
1083 | /* non hex character, so we abort and just |
1084 | * send the whole thing unescaped (including \x) |
1085 | */ |
1086 | sk_write(p->sub_socket, "\\", 1); |
1087 | eo = so + 1; |
1088 | break; |
1089 | } |
1090 | |
1091 | /* we only extract two hex characters */ |
1092 | if (i == 1) { |
1093 | sk_write(p->sub_socket, &v, 1); |
1094 | eo++; |
1095 | break; |
1096 | } |
1097 | |
1098 | i++; |
1099 | v <<= 4; |
1100 | } |
1101 | } |
1102 | break; |
1103 | |
1104 | default: |
1105 | sk_write(p->sub_socket, |
1106 | cfg.proxy_telnet_command + so, 2); |
1107 | eo++; |
1108 | break; |
1109 | } |
1110 | } else { |
1111 | |
1112 | /* % escape. we recognize %%, %host, %port. anything else, |
1113 | * we just send unescaped (including the %). */ |
1114 | |
1115 | if (cfg.proxy_telnet_command[eo] == '%') { |
1116 | sk_write(p->sub_socket, "%", 1); |
1117 | eo++; |
1118 | } |
1119 | else if (strnicmp(cfg.proxy_telnet_command + eo, |
1120 | "host", 4) == 0) { |
1121 | char dest[64]; |
1122 | sk_getaddr(p->remote_addr, dest, 64); |
1123 | sk_write(p->sub_socket, dest, strlen(dest)); |
1124 | eo += 4; |
1125 | } |
1126 | else if (strnicmp(cfg.proxy_telnet_command + eo, |
1127 | "port", 4) == 0) { |
1128 | char port[8]; |
1129 | sprintf(port, "%i", p->remote_port); |
1130 | sk_write(p->sub_socket, port, strlen(port)); |
1131 | eo += 4; |
1132 | } |
1133 | else { |
1134 | /* we don't escape this, so send the % now, and |
1135 | * don't advance eo, so that we'll consider the |
1136 | * text immediately following the % as unescaped. |
1137 | */ |
1138 | sk_write(p->sub_socket, "%", 1); |
1139 | } |
1140 | } |
1141 | |
1142 | /* resume scanning for additional escapes after this one. */ |
1143 | so = eo; |
1144 | } |
1145 | |
1146 | /* if there is any unescaped text at the end of the line, send it */ |
1147 | if (eo != so) { |
1148 | sk_write(p->sub_socket, cfg.proxy_telnet_command + so, eo - so); |
1149 | } |
1150 | |
1151 | p->state = 1; |
0e8f4cda |
1152 | return 0; |
1153 | } |
1154 | |
1155 | if (change == PROXY_CHANGE_CLOSING) { |
1156 | /* if our proxy negotiation process involves closing and opening |
1157 | * new sockets, then we would want to intercept this closing |
1158 | * callback when we were expecting it. if we aren't anticipating |
1159 | * a socket close, then some error must have occurred. we'll |
1160 | * just pass those errors up to the backend. |
1161 | */ |
1162 | return plug_closing(p->plug, p->closing_error_msg, |
1163 | p->closing_error_code, |
1164 | p->closing_calling_back); |
1165 | } |
1166 | |
1167 | if (change == PROXY_CHANGE_SENT) { |
1168 | /* some (or all) of what we wrote to the proxy was sent. |
1169 | * we don't do anything new, however, until we receive the |
1170 | * proxy's response. we might want to set a timer so we can |
1171 | * timeout the proxy negotiation after a while... |
1172 | */ |
1173 | return 0; |
1174 | } |
1175 | |
1176 | if (change == PROXY_CHANGE_ACCEPTING) { |
1177 | /* we should _never_ see this, as we are using our socket to |
1178 | * connect to a proxy, not accepting inbound connections. |
1179 | * what should we do? close the socket with an appropriate |
1180 | * error message? |
1181 | */ |
1182 | return plug_accepting(p->plug, p->accepting_sock); |
1183 | } |
1184 | |
1185 | if (change == PROXY_CHANGE_RECEIVE) { |
1186 | /* we have received data from the underlying socket, which |
1187 | * we'll need to parse, process, and respond to appropriately. |
1188 | */ |
1189 | |
1190 | /* we're done */ |
1191 | proxy_activate(p); |
1192 | /* proxy activate will have dealt with |
1193 | * whatever is left of the buffer */ |
1194 | return 1; |
1195 | } |
1196 | |
1197 | plug_closing(p->plug, "Network error: Unexpected proxy error", |
1198 | PROXY_ERROR_UNEXPECTED, 0); |
6971bbe7 |
1199 | return 1; |
8eebd221 |
1200 | } |